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7,100 | A-10s flew 32 percent of combat sorties in Operation Iraqi Freedom and Operation Enduring Freedom. The sorties ranged from 27,800 to 34,500 annually between 2009 and 2012. In the first half of 2013, they flew 11,189 sorties in Afghanistan. From the beginning of 2006 to October 2013, A-10s conducted 19 percent of CAS missions in Iraq and Afghanistan, more than the F-15E Strike Eagle and B-1B Lancer, but less than the 33 percent flown by F-16s. | https://en.wikipedia.org/wiki?curid=12502446 |
7,101 | In March 2011, six A-10s were deployed as part of Operation Odyssey Dawn, the coalition intervention in Libya. They participated in attacks on Libyan ground forces there. | https://en.wikipedia.org/wiki?curid=12502446 |
7,102 | The USAF 122nd Fighter Wing revealed it would deploy to the Middle East in October 2014 with 12 of the unit's 21 A-10 aircraft. Although the deployment had been planned a year in advance in a support role, the timing coincided with the ongoing Operation Inherent Resolve against ISIL militants. From mid-November, U.S. commanders began sending A-10s to hit IS targets in central and northwestern Iraq on an almost daily basis. In about two months time, A-10s flew 11 percent of all USAF sorties since the start of operations in August 2014. On 15 November 2015, two days after the ISIL attacks in Paris, A-10s and AC-130s destroyed a convoy of over 100 ISIL-operated oil tanker trucks in Syria. The attacks were part of an intensification of the U.S.-led intervention against ISIL called Operation Tidal Wave II (named after Operation Tidal Wave during World War II, a failed attempt to raid German oil fields) in an attempt to cut off oil smuggling as a source of funding for the group. | https://en.wikipedia.org/wiki?curid=12502446 |
7,103 | The A-10 has been involved with killing ten U.S. troops in friendly-fire over four incidents between 2001 to 2015 and 35 Afghan civilians from 2010 to 2015, more than any other U.S. military aircraft; these incidents have been assessed as "inconclusive and statistically insignificant" in terms of the warplane's capability. | https://en.wikipedia.org/wiki?curid=12502446 |
7,104 | On 19 January 2018, 12 A-10s from the 303d Expeditionary Fighter Squadron were deployed to Kandahar Airfield, Afghanistan, to provide close-air support, marking the first time in more than three years A-10s had been deployed to Afghanistan. | https://en.wikipedia.org/wiki?curid=12502446 |
7,105 | The future of the platform remains the subject of debate. In 2007, the USAF expected the A-10 to remain in service until 2028 and possibly later, when it would likely be replaced by the Lockheed Martin F-35 Lightning II. However, critics have said that replacing the A-10 with the F-35 would be a "giant leap backwards" given the A-10's performance and the F-35's high costs. In 2012, the Air Force considered the F-35B STOVL variant as a replacement CAS aircraft, but concluded that the aircraft could not generate sufficient sorties. In August 2013, Congress and the Air Force examined various proposals, including the F-35 and the MQ-9 Reaper unmanned aerial vehicle filling the A-10's role. Proponents state that the A-10's armor and cannon are superior to aircraft such as the F-35 for ground attack, that guided munitions other planes rely upon could be jammed, and that ground commanders frequently request A-10 support. | https://en.wikipedia.org/wiki?curid=12502446 |
7,106 | In the USAF's FY 2015 budget, the service considered retiring the A-10 and other single-mission aircraft, prioritizing multi-mission aircraft; cutting a whole fleet and its infrastructure was seen as the only method for major savings. The U.S. Army had expressed interest in obtaining some A-10s should the Air Force retire them, but later stated there was "no chance" of that happening. The U.S. Air Force stated that retirement would save $3.7 billion from 2015 to 2019. The prevalence of guided munitions allows more aircraft to perform the CAS mission and reduces the requirement for specialized aircraft; since 2001 multirole aircraft and bombers have performed 80 percent of operational CAS missions. The Air Force also said that the A-10 was more vulnerable to advanced anti-aircraft defenses, but the Army replied that the A-10 had proved invaluable because of its versatile weapons loads, psychological impact, and limited logistics needs on ground support systems. | https://en.wikipedia.org/wiki?curid=12502446 |
7,107 | In January 2015, USAF officials told lawmakers that it would take 15 years to fully develop a new attack aircraft to replace the A-10; that year General Herbert J. Carlisle, the head of Air Combat Command, stated that a follow-on weapon system for the A-10 may need to be developed. It planned for F-16s and F-15Es to initially take up CAS sorties, and later by the F-35A once sufficient numbers become operationally available over the next decade. In July 2015, Boeing held initial discussions on the prospects of selling retired or stored A-10s in near-flyaway condition to international customers. However, the Air Force then said that it would not permit the aircraft to be sold. | https://en.wikipedia.org/wiki?curid=12502446 |
7,108 | Plans to develop a replacement aircraft were announced by the US Air Combat Command in August 2015. Early the following year, the Air Force began studying future CAS aircraft to succeed the A-10 in low-intensity "permissive conflicts" like counterterrorism and regional stability operations, admitting that the F-35 would be too expensive to operate in day-to-day roles. A wide range of platforms were under consideration, including everything from low-end AT-6 Wolverine and A-29 Super Tucano turboprops and the Textron AirLand Scorpion as more basic off-the-shelf options to more sophisticated clean-sheet attack aircraft or "AT-X" derivatives of the T-X next-generation trainer as entirely new attack platforms. | https://en.wikipedia.org/wiki?curid=12502446 |
7,109 | In January 2016, the USAF was "indefinitely freezing" plans to retire the A-10 for at least several years. In addition to Congressional opposition, its use in anti-ISIS operations, deployments to Eastern Europe as a response to Russia's military intervention in Ukraine, and reevaluation of F-35 numbers necessitated its retention. In February 2016, the Air Force deferred the final retirement of the aircraft until 2022 after being replaced by F-35s on a squadron-by-squadron basis. In October 2016, the Air Force Materiel Command brought the depot maintenance line back to full capacity in preparation for re-winging the fleet. In June 2017, it was announced that the aircraft "...will now be kept in the air force’s inventory indefinitely." The 2022 Russian invasion of Ukraine spurred some American observers to push for the loaning of A-10s to Ukraine, particularly following reports of an extended, stalled Russian convoy outside Kyiv, with critics of such a proposal noting the diplomatic and tactical complications to such an approach. | https://en.wikipedia.org/wiki?curid=12502446 |
7,110 | On 25 March 2010, an A-10 conducted the first flight of an aircraft with all engines powered by a biofuel blend. The flight, performed at Eglin Air Force Base, used a 1:1 blend of JP-8 and Camelina-based fuel. On 28 June 2012, the A-10 became the first aircraft to fly using a new fuel blend derived from alcohol; known as ATJ (Alcohol-to-Jet), the fuel is cellulosic-based and can be produced using wood, paper, grass, or any cellulose based material, which are fermented into alcohols before being hydro-processed into aviation fuel. ATJ is the third alternative fuel to be evaluated by the Air Force as a replacement for the petroleum-derived JP-8 fuel. Previous types were a synthetic paraffinic kerosene derived from coal and natural gas and a bio-mass fuel derived from plant-oils and animal fats known as Hydroprocessed Renewable Jet. | https://en.wikipedia.org/wiki?curid=12502446 |
7,111 | In 2011, the National Science Foundation granted $11 million to modify an A-10 for weather research for CIRPAS at the U.S. Naval Postgraduate School and in collaboration with scientists from the South Dakota School of Mines & Technology (SDSM&T), replacing SDSM&T's retired North American T-28 Trojan. The A-10's armor is expected to allow it to survive the extreme meteorological conditions, such as 200 mph hailstorms, found in inclement high-altitude weather events. In 2018, this plan was found to carry too many risks associated with the costly modifications required and the program was cancelled. | https://en.wikipedia.org/wiki?curid=12502446 |
7,112 | The A-10 has been flown exclusively by the United States Air Force and its Air Reserve components, the Air Force Reserve Command (AFRC) and the Air National Guard (ANG). , 282 A-10C aircraft are reported as operational, divided as follows: 141 USAF, 55 AFRC, 86 ANG. | https://en.wikipedia.org/wiki?curid=12502446 |
7,113 | The A-10 Thunderbolt II received its popular nickname "Warthog" from the pilots and crews of the USAF attack squadrons who flew and maintained it. The A-10 is the last of Republic's jet attack aircraft to serve with the USAF. The Republic F-84 Thunderjet was nicknamed the "Hog", F-84F Thunderstreak nicknamed "Superhog", and the Republic F-105 Thunderchief tagged "Ultra Hog". The saying "Go Ugly Early" has been associated with the aircraft in reference to calling in the A-10 early to support troops in ground combat. | https://en.wikipedia.org/wiki?curid=12502446 |
7,114 | In economics, the Gini coefficient ( ), also known as the Gini index or Gini ratio, is a measure of statistical dispersion intended to represent the income inequality or the wealth inequality within a nation or a social group. The Gini coefficient was developed by the statistician and sociologist Corrado Gini. | https://en.wikipedia.org/wiki?curid=12883 |
7,115 | The Gini coefficient measures the inequality among values of a frequency distribution, such as the levels of income. A Gini coefficient of 0 reflects "perfect equality", where all income or wealth values are the same, while a Gini coefficient of 1 (or 100%) reflects "maximal inequality" among values. For example, if everyone has the same income, the Gini coefficient will be 0. In contrast, if for a large number of people only one person has all the income or consumption and all others have none, the Gini coefficient will be 1. | https://en.wikipedia.org/wiki?curid=12883 |
7,116 | The Gini coefficient was proposed by Corrado Gini as a measure of inequality of income or wealth. For OECD countries, in the late 20th century, considering the effect of taxes and transfer payments, the income Gini coefficient ranged between 0.24 and 0.49, with Slovenia being the lowest and Mexico the highest. African countries had the highest pre-tax Gini coefficients in 2008–2009, with South Africa having the world's highest, variously estimated to be 0.63 to 0.7, although this figure drops to 0.52 after social assistance is taken into account, and drops again to 0.47 after taxation. The global income Gini coefficient in 2005 has been estimated to be between 0.61 and 0.68 by various sources. | https://en.wikipedia.org/wiki?curid=12883 |
7,117 | There are some issues in interpreting a Gini coefficient; the same value may result from many different distribution curves. The demographic structure should be taken into account. Countries with an aging population or with an increased birth rate experience an increasing pre-tax Gini coefficient even if real income distribution for working adults remains constant. Scholars have devised over a dozen variants of the Gini coefficient. | https://en.wikipedia.org/wiki?curid=12883 |
7,118 | The Gini coefficient was developed by the Italian statistician Corrado Gini and published in his 1912 paper "Variability and Mutability" (). Building on the work of American economist Max Lorenz, Gini proposed that the difference between the hypothetical straight line depicting perfect equality, and the actual line depicting people's incomes, be used as a measure of inequality. | https://en.wikipedia.org/wiki?curid=12883 |
7,119 | The Gini coefficient is an index for the degree of inequality in the distribution of income/wealth, used to estimate how far a country's wealth or income distribution deviates from an equal distribution. | https://en.wikipedia.org/wiki?curid=12883 |
7,120 | The Gini coefficient is usually defined mathematically based on the Lorenz curve, which plots the proportion of the total income of the population (y-axis) that is cumulatively earned by the bottom "x" of the population (see diagram). The line at 45 degrees thus represents perfect equality of incomes. The Gini coefficient can then be thought of as the ratio of the area that lies between the line of equality and the Lorenz curve (marked "A" in the diagram) over the total area under the line of equality (marked "A" and "B" in the diagram); i.e., . If there are no negative incomes, it is also equal to 2"A" and to due to the fact that . | https://en.wikipedia.org/wiki?curid=12883 |
7,121 | Suppose all people have non-negative income (or wealth, as the case may be). In that case, the Gini coefficient can theoretically range from 0 (complete equality) to 1 (complete inequality) and is sometimes expressed as a percentage ranging between 0 and 100. If negative values are possible (such as the wealth of people with debts), then the Gini coefficient could theoretically be more than 1. Usually, the mean (or total) is assumed to be positive, which rules out a Gini coefficient of less than zero. | https://en.wikipedia.org/wiki?curid=12883 |
7,122 | An alternative approach is to define the Gini coefficient as half of the relative mean absolute difference, which is mathematically equivalent to the definition based on the Lorenz curve. The mean absolute difference is the average absolute difference of all pairs of items of the population, and the relative mean absolute difference is the mean absolute difference divided by the average, formula_1, to normalize for scale. If "x" is the wealth or income of person "i", and there are "n" persons, then the Gini coefficient "G" is given by: | https://en.wikipedia.org/wiki?curid=12883 |
7,123 | When the income (or wealth) distribution is given as a continuous probability density function "p"("x"), the Gini coefficient is again half of the relative mean absolute difference: | https://en.wikipedia.org/wiki?curid=12883 |
7,124 | where formula_4 is the mean of the distribution, and the lower limits of integration may be replaced by zero when all incomes are positive. | https://en.wikipedia.org/wiki?curid=12883 |
7,125 | While the income distribution of any particular country will not always follow theoretical models, in reality, these models give a qualitative understanding of the income distribution in a nation given the Gini coefficient. | https://en.wikipedia.org/wiki?curid=12883 |
7,126 | The extreme cases are represented by the "most equal" society in which every person receives the same income () and the "most unequal" society (composed of "N" individuals) where a single person receives 100% of the total income and the remaining people receive none (). | https://en.wikipedia.org/wiki?curid=12883 |
7,127 | A simplified case distinguishes just two levels of income, low and high. If the high income group is a proportion "u" of the population and earns a proportion "f" of all income, then the Gini coefficient is . A more graded distribution with these same values "u" and "f" will always have a higher Gini coefficient than . | https://en.wikipedia.org/wiki?curid=12883 |
7,128 | An example case in which the richest 20% of the population have 80% of all income (see Pareto principle) would lead to an income Gini coefficient of at least 60%. | https://en.wikipedia.org/wiki?curid=12883 |
7,129 | Another example case in which 1% of all the world's population owns 50% of all wealth, would result in a wealth Gini coefficient of at least 49%. | https://en.wikipedia.org/wiki?curid=12883 |
7,130 | In some cases, this equation can be applied to calculate the Gini coefficient without direct reference to the Lorenz curve. For example, (taking "y" to indicate the income or wealth of a person or household): | https://en.wikipedia.org/wiki?curid=12883 |
7,131 | Since the Gini coefficient is half the relative mean absolute difference, it can also be calculated using formulas for the relative mean absolute difference. For a random sample "S" consisting of values "y", "i" = 1 to "n", that are indexed in non-decreasing order ("y" ≤ "y"), the statistic: | https://en.wikipedia.org/wiki?curid=12883 |
7,132 | is a consistent estimator of the population Gini coefficient, but is not, in general, unbiased. Like "G", has a simpler form: | https://en.wikipedia.org/wiki?curid=12883 |
7,133 | There does not exist a sample statistic that is, in general, an unbiased estimator of the population Gini coefficient, like the relative mean absolute difference. | https://en.wikipedia.org/wiki?curid=12883 |
7,134 | For a discrete probability distribution with probability mass function formula_9 formula_10, where formula_11 is the fraction of the population with income or wealth formula_12, the Gini coefficient is: | https://en.wikipedia.org/wiki?curid=12883 |
7,135 | When the population is large, the income distribution may be represented by a continuous probability density function "f"("x") where "f"("x") "dx" is the fraction of the population with wealth or income in the interval "dx" about "x". If "F"("x") is the cumulative distribution function for "f"("x"): | https://en.wikipedia.org/wiki?curid=12883 |
7,136 | then the Lorenz curve "L"("F") may then be represented as a function parametric in "L"("x") and "F"("x") and the value of "B" can be found by integration: | https://en.wikipedia.org/wiki?curid=12883 |
7,137 | The Gini coefficient can also be calculated directly from the cumulative distribution function of the distribution "F"("y"). Defining μ as the mean of the distribution, and specifying that "F"("y") is zero for all negative values, the Gini coefficient is given by: | https://en.wikipedia.org/wiki?curid=12883 |
7,138 | The latter result comes from integration by parts. (Note that this formula can be applied when there are negative values if the integration is taken from minus infinity to plus infinity.) | https://en.wikipedia.org/wiki?curid=12883 |
7,139 | The Gini coefficient may be expressed in terms of the quantile function "Q"("F") (inverse of the cumulative distribution function: "Q"("F"("x")) = "x") | https://en.wikipedia.org/wiki?curid=12883 |
7,140 | Since the Gini coefficient is independent of scale, if the distribution function can be expressed in the form "f(x,φ,a,b,c...)" where "φ" is a scale factor and "a,b,c..." are dimensionless parameters, then the Gini coefficient will be a function only of "a,b,c...". For example, for the exponential distribution, which is a function of only "x" and a scale parameter, the Gini coefficient is a constant, equal to 1/2. | https://en.wikipedia.org/wiki?curid=12883 |
7,141 | For some functional forms, the Gini index can be calculated explicitly. For example, if "y" follows a log-normal distribution with the standard deviation of logs equal to formula_25, then formula_26 where formula_27 is the error function ( since formula_28, where formula_29 is the cumulative distribution function of a standard normal distribution). In the table below, some examples for probability density functions with support on formula_30 are shown. The Dirac delta distribution represents the case where everyone has the same wealth (or income); it implies no variations between incomes. | https://en.wikipedia.org/wiki?curid=12883 |
7,142 | Sometimes the entire Lorenz curve is not known, and only values at certain intervals are given. In that case, the Gini coefficient can be approximated using various techniques for interpolating the missing values of the Lorenz curve. If ("X", "Y") are the known points on the Lorenz curve, with the "X" indexed in increasing order ("X" < "X"), so that: | https://en.wikipedia.org/wiki?curid=12883 |
7,143 | If the Lorenz curve is approximated on each interval as a line between consecutive points, then the area B can be approximated with trapezoids and: | https://en.wikipedia.org/wiki?curid=12883 |
7,144 | is the resulting approximation for G. More accurate results can be obtained using other methods to approximate the area B, such as approximating the Lorenz curve with a quadratic function across pairs of intervals or building an appropriately smooth approximation to the underlying distribution function that matches the known data. If the population mean and boundary values for each interval are also known, these can also often be used to improve the accuracy of the approximation. | https://en.wikipedia.org/wiki?curid=12883 |
7,145 | The Gini coefficient calculated from a sample is a statistic, and its standard error, or confidence intervals for the population Gini coefficient, should be reported. These can be calculated using bootstrap techniques, mathematically complicated and computationally demanding even in an era of fast computers. Economist Tomson Ogwang made the process more efficient by setting up a "trick regression model" in which respective income variables in the sample are ranked, with the lowest income being allocated rank 1. The model then expresses the rank (dependent variable) as the sum of a constant "A" and a normal error term whose variance is inversely proportional to "y": | https://en.wikipedia.org/wiki?curid=12883 |
7,146 | Thus, "G" can be expressed as a function of the weighted least squares estimate of the constant "A" and that this can be used to speed up the calculation of the jackknife estimate for the standard error. Economist David Giles argued that the standard error of the estimate of "A" can be used to derive the estimate of "G" directly without using a jackknife. This method only requires using ordinary least squares regression after ordering the sample data. The results compare favorably with the estimates from the jackknife with agreement improving with increasing sample size. | https://en.wikipedia.org/wiki?curid=12883 |
7,147 | However, it has been argued that this depends on the model's assumptions about the error distributions and the independence of error terms. These assumptions are often not valid for real data sets. There is still ongoing debate surrounding this topic. | https://en.wikipedia.org/wiki?curid=12883 |
7,148 | Guillermina Jasso and Angus Deaton independently proposed the following formula for the Gini coefficient: | https://en.wikipedia.org/wiki?curid=12883 |
7,149 | where formula_37 is mean income of the population, P is the income rank P of person i, with income X, such that the richest person receives a rank of 1 and the poorest a rank of "N". This effectively gives higher weight to poorer people in the income distribution, which allows the Gini to meet the Transfer Principle. Note that the Jasso-Deaton formula rescales the coefficient so that its value is one if all the formula_38 are zero except one. Note however Allison's reply on the need to divide by N² instead. | https://en.wikipedia.org/wiki?curid=12883 |
7,150 | The Gini coefficient and other standard inequality indices reduce to a common form. Perfect equality—the absence of inequality—exists when and only when the inequality ratio, formula_39, equals 1 for all j units in some population (for example, there is perfect income equality when everyone's income formula_40 equals the mean income formula_41, so that formula_42 for everyone). Measures of inequality, then, are measures of the average deviations of the formula_42 from 1; the greater the average deviation, the greater the inequality. Based on these observations the inequality indices have this common form: | https://en.wikipedia.org/wiki?curid=12883 |
7,151 | where "p" weights the units by their population share, and "f"("r") is a function of the deviation of each unit's "r" from 1, the point of equality. The insight of this generalised inequality index is that inequality indices differ because they employ different functions of the distance of the inequality ratios (the "r") from 1. | https://en.wikipedia.org/wiki?curid=12883 |
7,152 | Gini coefficients of income are calculated on a market income and a disposable income basis. The Gini coefficient on market income—sometimes referred to as a pre-tax Gini coefficient—is calculated on income before taxes and transfers. It measures inequality in income without considering the effect of taxes and social spending already in place in a country. The Gini coefficient on disposable income—sometimes referred to as the after-tax Gini coefficient—is calculated on income after taxes and transfers. It measures inequality in income after considering the effect of taxes and social spending already in place in a country. | https://en.wikipedia.org/wiki?curid=12883 |
7,153 | For OECD countries over the 2008–2009 period, the Gini coefficient (pre-taxes and transfers) for a total population ranged between 0.34 and 0.53, with South Korea the lowest and Italy the highest. The Gini coefficient (after-taxes and transfers) for a total population ranged between 0.25 and 0.48, with Denmark the lowest and Mexico the highest. For the United States, the country with the largest population among OECD countries, the pre-tax Gini index was 0.49, and the after-tax Gini index was 0.38 in 2008–2009. The OECD average for total populations in OECD countries was 0.46 for the pre-tax income Gini index and 0.31 for the after-tax income Gini index. Taxes and social spending that were in place in 2008–2009 period in OECD countries significantly lowered effective income inequality, and in general, "European countries—especially Nordic and Continental welfare states—achieve lower levels of income inequality than other countries." | https://en.wikipedia.org/wiki?curid=12883 |
7,154 | Using the Gini can help quantify differences in welfare and compensation policies and philosophies. However, it should be borne in mind that the Gini coefficient can be misleading when used to make political comparisons between large and small countries or those with different immigration policies (see limitations section). | https://en.wikipedia.org/wiki?curid=12883 |
7,155 | The Gini coefficient for the entire world has been estimated by various parties to be between 0.61 and 0.68. The graph shows the values expressed as a percentage in their historical development for a number of countries. | https://en.wikipedia.org/wiki?curid=12883 |
7,156 | According to UNICEF, Latin America and the Caribbean region had the highest net income Gini index in the world at 48.3, on an unweighted average basis in 2008. The remaining regional averages were: sub-Saharan Africa (44.2), Asia (40.4), Middle East and North Africa (39.2), Eastern Europe and Central Asia (35.4), and High-income Countries (30.9). Using the same method, the United States is claimed to have a Gini index of 36, while South Africa had the highest income Gini index score of 67.8. | https://en.wikipedia.org/wiki?curid=12883 |
7,157 | Taking income distribution of all human beings, worldwide income inequality has been constantly increasing since the early 19th century. There was a steady increase in the global income inequality Gini score from 1820 to 2002, with a significant increase between 1980 and 2002. This trend appears to have peaked and begun a reversal with rapid economic growth in emerging economies, particularly in the large populations of BRIC countries. | https://en.wikipedia.org/wiki?curid=12883 |
7,158 | The table below presents the estimated world income Gini coefficients over the last 200 years, as calculated by Milanovic. | https://en.wikipedia.org/wiki?curid=12883 |
7,159 | More detailed data from similar sources plots a continuous decline since 1988. This is attributed to globalization increasing incomes for billions of poor people, mostly in countries like China and India. Developing countries like Brazil have also improved basic services like health care, education, and sanitation; others like Chile and Mexico have enacted more progressive tax policies. | https://en.wikipedia.org/wiki?curid=12883 |
7,160 | The Gini coefficient is widely used in fields as diverse as sociology, economics, health science, ecology, engineering, and agriculture. For example, in social sciences and economics, in addition to income Gini coefficients, scholars have published education Gini coefficients and opportunity Gini coefficients. | https://en.wikipedia.org/wiki?curid=12883 |
7,161 | Education Gini index estimates the inequality in education for a given population. It is used to discern trends in social development through educational attainment over time. A study across 85 countries by three World Bank economists, Vinod Thomas, Yan Wang, and Xibo Fan, estimated Mali had the highest education Gini index of 0.92 in 1990 (implying very high inequality in educational attainment across the population), while the United States had the lowest education inequality Gini index of 0.14. Between 1960 and 1990, China, India and South Korea had the fastest drop in education inequality Gini Index. They also claim education Gini index for the United States slightly increased over the 1980–1990 period. | https://en.wikipedia.org/wiki?curid=12883 |
7,162 | Similar in concept to the Gini income coefficient, the Gini opportunity coefficient measures inequality in opportunities. The concept builds on Amartya Sen's suggestion that inequality coefficients of social development should be premised on the process of enlarging people's choices and enhancing their capabilities, rather than on the process of reducing income inequality. Kovacevic, in a review of the Gini opportunity coefficient, explained that the coefficient estimates how well a society enables its citizens to achieve success in life where the success is based on a person's choices, efforts and talents, not his background defined by a set of predetermined circumstances at birth, such as gender, race, place of birth, parent's income and circumstances beyond the control of that individual. | https://en.wikipedia.org/wiki?curid=12883 |
7,163 | In 2003, Roemer reported Italy and Spain exhibited the largest opportunity inequality Gini index amongst advanced economies. | https://en.wikipedia.org/wiki?curid=12883 |
7,164 | In 1978, Anthony Shorrocks introduced a measure based on income Gini coefficients to estimate income mobility. This measure, generalized by Maasoumi and Zandvakili, is now generally referred to as Shorrocks index, sometimes as Shorrocks mobility index or Shorrocks rigidity index. It attempts to estimate whether the income inequality Gini coefficient is permanent or temporary and to what extent a country or region enables economic mobility to its people so that they can move from one (e.g., bottom 20%) income quantile to another (e.g., middle 20%) over time. In other words, the Shorrocks index compares inequality of short-term earnings, such as the annual income of households, to inequality of long-term earnings, such as 5-year or 10-year total income for the same households. | https://en.wikipedia.org/wiki?curid=12883 |
7,165 | Shorrocks index is calculated in several different ways, a common approach being from the ratio of income Gini coefficients between short-term and long-term for the same region or country. | https://en.wikipedia.org/wiki?curid=12883 |
7,166 | A 2010 study using social security income data for the United States since 1937 and Gini-based Shorrock's indices concludes that income mobility in the United States has had a complicated history, primarily due to the mass influx of women into the American labor force after World War II. Income inequality and income mobility trends have been different for men and women workers between 1937 and the 2000s. When men and women are considered together, the Gini coefficient-based Shorrocks index trends imply long-term income inequality has been substantially reduced among all workers, in recent decades for the United States. Other scholars, using just 1990s data or other short periods have come to different conclusions. For example, Sastre and Ayala conclude from their study of income Gini coefficient data between 1993 and 1998 for six developed economies that France had the least income mobility, Italy the highest, and the United States and Germany intermediate levels of income mobility over those five years. | https://en.wikipedia.org/wiki?curid=12883 |
7,167 | The Gini coefficient has features that make it useful as a measure of dispersion in a population, and inequalities in particular. | https://en.wikipedia.org/wiki?curid=12883 |
7,168 | The Gini coefficient is a relative measure. The Gini coefficient of a developing country can rise (due to increasing inequality of income) even when the number of people in absolute poverty decreases. This is because the Gini coefficient measures relative, not absolute, wealth. Changing income inequality, measured by Gini coefficients, can be due to structural changes in a society such as growing population (increased birth rates, aging populations, increased divorce rates, extended family households splitting into nuclear families, emigration, immigration) and income mobility. Gini coefficients are simple, and this simplicity can lead to oversights and can confuse the comparison of different populations; for example, while both Bangladesh (per capita income of $1,693) and the Netherlands (per capita income of $42,183) had an income Gini coefficient of 0.31 in 2010, the quality of life, economic opportunity and absolute income in these countries are very different, i.e. countries may have identical Gini coefficients, but differ greatly in wealth. Basic necessities may be available to all in a developed economy, while in an undeveloped economy with the same Gini coefficient, basic necessities may be unavailable to most or unequally available due to lower absolute wealth. | https://en.wikipedia.org/wiki?curid=12883 |
7,169 | Even when the total income of a population is the same, in certain situations two countries with different income distributions can have the same Gini index (e.g. cases when income Lorenz Curves cross). Table A illustrates one such situation. Both countries have a Gini coefficient of 0.2, but the average income distributions for household groups are different. As another example, in a population where the lowest 50% of individuals have no income, and the other 50% have equal income, the Gini coefficient is 0.5; whereas for another population where the lowest 75% of people have 25% of income and the top 25% have 75% of the income, the Gini index is also 0.5. Economies with similar incomes and Gini coefficients can have very different income distributions. Bellù and Liberati claim that ranking income inequality between two populations is not always possible based on their Gini indices. Similarly, computational social scientist Fabian Stephany illustrates that income inequality within the population, e.g., in specific socio-economic groups of same age and education, also remains undetected by conventional Gini indices. | https://en.wikipedia.org/wiki?curid=12883 |
7,170 | A Gini index does not contain information about absolute national or personal incomes. Populations can simultaneously have very low-income Gini indices and very high wealth Gini indexes. By measuring inequality in income, the Gini ignores the differential efficiency of the use of household income. By ignoring wealth (except as it contributes to income), the Gini can create the appearance of inequality when the people compared are at different stages in their life. Wealthy countries such as Sweden can show a low Gini coefficient for the disposable income of 0.31, thereby appearing equal, yet have a very high Gini coefficient for wealth of 0.79 to 0.86, suggesting an extremely unequal wealth distribution in its society. These factors are not assessed in income-based Gini. | https://en.wikipedia.org/wiki?curid=12883 |
7,171 | Gini index has a downward-bias for small populations. Counties or states or countries with small populations and less diverse economies will tend to report small Gini coefficients. For economically diverse large population groups, a much higher coefficient is expected than for each of its regions. For example, taking the world economy as a whole and income distribution for all human beings, different scholars estimate the global Gini index to range between 0.61 and 0.68. | https://en.wikipedia.org/wiki?curid=12883 |
7,172 | As with other inequality coefficients, the Gini coefficient is influenced by the granularity of the measurements. For example, five 20% quantiles (low granularity) will usually yield a lower Gini coefficient than twenty 5% quantiles (high granularity) for the same distribution. Philippe Monfort has shown that using inconsistent or unspecified granularity limits the usefulness of Gini coefficient measurements. | https://en.wikipedia.org/wiki?curid=12883 |
7,173 | The Gini coefficient measure gives different results when applied to individuals instead of households, for the same economy and same income distributions. If household data is used, the measured value of income Gini depends on how the household is defined. The comparison is not meaningful when different populations are not measured with consistent definitions. | https://en.wikipedia.org/wiki?curid=12883 |
7,174 | Deininger and Squire (1996) show that the income Gini coefficient based on individual income rather than household income is different. For example, for the United States, they found that the individual income-based Gini index was 0.35, while for France, 0.43. According to their individual-focused method, in the 108 countries they studied, South Africa had the world's highest Gini coefficient at 0.62, Malaysia had Asia's highest Gini coefficient at 0.5, Brazil the highest at 0.57 in Latin America and the Caribbean region, and Turkey the highest at 0.5 in OECD countries. | https://en.wikipedia.org/wiki?curid=12883 |
7,175 | Expanding on the importance of life-span measures, the Gini coefficient as a point-estimate of equality at a certain time ignores life-span changes in income. Typically, increases in the proportion of young or old members of a society will drive apparent changes in equality simply because people generally have lower incomes and wealth when they are young than when they are old. Because of this, factors such as age distribution within a population and mobility within income classes can create the appearance of inequality when none exist, taking into account demographic effects. Thus a given economy may have a higher Gini coefficient at any timepoint compared to another, while the Gini coefficient calculated over individuals' lifetime income is lower than the apparently more equal (at a given point in time) economy's. Essentially, what matters is not just inequality in any particular year but the distribution composition over time. | https://en.wikipedia.org/wiki?curid=12883 |
7,176 | Billionaire Thomas Kwok claimed the income Gini coefficient for Hong Kong has been high (0.434 in 2010), in part because of structural changes in its population. Over recent decades, Hong Kong has witnessed increasing numbers of small households, elderly households and elderly living alone. The combined income is now split into more households. Many older people live separate from their children in Hong Kong. These social changes have caused substantial changes in household income distribution. The income Gini coefficient, claims Kwok, does not discern these structural changes in its society. Household money income distribution for the United States, summarized in Table C of this section, confirms that this issue is not limited to just Hong Kong. According to the US Census Bureau, between 1979 and 2010, the population of the United States experienced structural changes in overall households; the income for all income brackets increased in inflation-adjusted terms, household income distributions shifted into higher income brackets over time, while the income Gini coefficient increased. | https://en.wikipedia.org/wiki?curid=12883 |
7,177 | Another limitation of the Gini coefficient is that it is not a proper measure of egalitarianism, as it only measures income dispersion. For example, suppose two equally egalitarian countries pursue different immigration policies. In that case, the country accepting a higher proportion of low-income or impoverished migrants will report a higher Gini coefficient and, therefore, may exhibit more income inequality. | https://en.wikipedia.org/wiki?curid=12883 |
7,178 | Some countries distribute benefits that are difficult to value. Countries that provide subsidized housing, medical care, education or other such services are difficult to value objectively, as it depends on the quality and extent of the benefit. In absence of a free market, valuing these income transfers as household income is subjective. The theoretical model of the Gini coefficient is limited to accepting correct or incorrect subjective assumptions. | https://en.wikipedia.org/wiki?curid=12883 |
7,179 | In subsistence-driven and informal economies, people may have significant income in other forms than money, for example, through subsistence farming or bartering. These income tend to accrue to the segment of population below the poverty line or very poor in emerging and transitional economy countries such as those in sub-Saharan Africa, Latin America, Asia and Eastern Europe. Informal economy accounts for over half of global employment and as much as 90 per cent of employment in some of the poorer sub-Saharan countries with high official Gini inequality coefficients. Schneider et al., in their 2010 study of 162 countries, report about 31.2%, or about $20 trillion, of world's GDP is informal. In developing countries, the informal economy predominates for all income brackets except the richer, urban upper-income bracket populations. Even in developed economies, 8% (United States) to 27% (Italy) of each nation's GDP is informal. The resulting informal income predominates as a livelihood activity for those in the lowest income brackets. The value and distribution of the incomes from informal or underground economy is difficult to quantify, making true income Gini coefficients estimates difficult. Different assumptions and quantifications of these incomes will yield different Gini coefficients. | https://en.wikipedia.org/wiki?curid=12883 |
7,180 | Gini has some mathematical limitations as well. It is not additive and different sets of people cannot be averaged to obtain the Gini coefficient of all the people in the sets. | https://en.wikipedia.org/wiki?curid=12883 |
7,181 | Given the limitations of the Gini coefficient, other statistical methods are used in combination or as an alternative measure of population dispersity. For example, "entropy measures" are frequently used (e.g. the Atkinson index or the Theil Index and Mean log deviation as special cases of the generalized entropy index). These measures attempt to compare the distribution of resources by intelligent agents in the market with a maximum entropy random distribution, which would occur if these agents acted like non-interacting particles in a closed system following the laws of statistical physics. | https://en.wikipedia.org/wiki?curid=12883 |
7,182 | There is a summary measure of the diagnostic ability of a binary classifier system that is also called the "Gini coefficient", which is defined as twice the area between the receiver operating characteristic (ROC) curve and its diagonal. It is related to the AUC (Area Under the ROC Curve) measure of performance given by formula_45 and to Mann–Whitney U. Although both Gini coefficients are defined as areas between certain curves and share certain properties, there is no simple direct relationship between the Gini coefficient of statistical dispersion and the Gini coefficient of a classifier. | https://en.wikipedia.org/wiki?curid=12883 |
7,183 | The Gini index is also related to the Pietra index — both of which measure statistical heterogeneity and are derived from the Lorenz curve and the diagonal line. | https://en.wikipedia.org/wiki?curid=12883 |
7,184 | In certain fields such as ecology, inverse Simpson's index formula_46 is used to quantify diversity, and this should not be confused with the Simpson index formula_47. These indicators are related to Gini. The inverse Simpson index increases with diversity, unlike the Simpson index and Gini coefficient, which decrease with diversity. The Simpson index is in the range [0, 1], where 0 means maximum and 1 means minimum diversity (or heterogeneity). Since diversity indices typically increase with increasing heterogeneity, the Simpson index is often transformed into inverse Simpson, or using the complement formula_48, known as the Gini-Simpson Index. | https://en.wikipedia.org/wiki?curid=12883 |
7,185 | In recent decades, researchers have attempted to estimate Gini coefficients for pre-20th century societies. In the absence of household income surveys and income taxes, scholars have relied on proxy variables. These include wealth taxes in medieval European city states, patterns of landownership in Roman Egypt, variation of the size of houses in societies from ancient Greece to Aztec Mexico, and inheritance and dowries in Babylonian society. Other data does not directly document variations in wealth or income but are known to reflect inequality, such as the ratio of rents to wages or of labor to capital. | https://en.wikipedia.org/wiki?curid=12883 |
7,186 | Although the Gini coefficient is most popular in economics, it can, in theory, be applied in any field of science that studies a distribution. For example, in ecology, the Gini coefficient has been used as a measure of biodiversity, where the cumulative proportion of species is plotted against the cumulative proportion of individuals. In health, it has been used as a measure of the inequality of health-related quality of life in a population. In education, it has been used as a measure of the inequality of universities. In chemistry it has been used to express the selectivity of protein kinase inhibitors against a panel of kinases. In engineering, it has been used to evaluate the fairness achieved by Internet routers in scheduling packet transmissions from different flows of traffic. | https://en.wikipedia.org/wiki?curid=12883 |
7,187 | The Gini coefficient is sometimes used for the measurement of the discriminatory power of rating systems in credit risk management. | https://en.wikipedia.org/wiki?curid=12883 |
7,188 | A 2005 study accessed US census data to measure home computer ownership and used the Gini coefficient to measure inequalities amongst whites and African Americans. Results indicated that although decreasing overall, home computer ownership inequality was substantially smaller among white households. | https://en.wikipedia.org/wiki?curid=12883 |
7,189 | A 2016 peer-reviewed study titled Employing the Gini coefficient to measure participation inequality in treatment-focused Digital Health Social Networks illustrated that the Gini coefficient was helpful and accurate in measuring shifts in inequality, however as a standalone metric it failed to incorporate overall network size. | https://en.wikipedia.org/wiki?curid=12883 |
7,190 | Discriminatory power refers to a credit risk model's ability to differentiate between defaulting and non-defaulting clients. The formula formula_49, in the calculation section above, may be used for the final model and at the individual model factor level to quantify the discriminatory power of individual factors. It is related to the accuracy ratio in population assessment models. | https://en.wikipedia.org/wiki?curid=12883 |
7,191 | Kaminskiy and Krivtsov extended the concept of the Gini coefficient from economics to reliability theory and proposed a Gini–type coefficient that helps to assess the degree of aging of non−repairable systems or aging and rejuvenation of repairable systems. The coefficient is defined between -1 and 1 and can be used in both empirical and parametric life distributions. It takes negative values for the class of decreasing failure rate distributions and point processes with decreasing failure intensity rate and is positive for the increasing failure rate distributions and point processes with increasing failure intensity rate. The value of zero corresponds to the exponential life distribution or the Homogeneous Poisson Process. | https://en.wikipedia.org/wiki?curid=12883 |
7,192 | The International Space Station (ISS) is the largest modular space station currently in low Earth orbit. It is a multinational collaborative project involving five participating space agencies: NASA (United States), Roscosmos (Russia), JAXA (Japan), ESA (Europe), and CSA (Canada). The ownership and use of the space station is established by intergovernmental treaties and agreements. The station serves as a microgravity and space environment research laboratory in which scientific research is conducted in astrobiology, astronomy, meteorology, physics, and other fields. The ISS is suited for testing the spacecraft systems and equipment required for possible future long-duration missions to the Moon and Mars. | https://en.wikipedia.org/wiki?curid=15043 |
7,193 | The ISS programme evolved from the Space Station "Freedom", a 1984 American proposal to construct a permanently crewed Earth-orbiting station, and the contemporaneous Soviet/Russian "Mir-2" proposal from 1976 with similar aims. The ISS is the ninth space station to be inhabited by crews, following the Soviet and later Russian "Salyut", Almaz, and "Mir" stations and the American Skylab. It is the largest artificial object in the solar system and the largest satellite in low Earth orbit, regularly visible to the naked eye from Earth's surface. It maintains an orbit with an average altitude of by means of reboost manoeuvres using the engines of the "Zvezda" Service Module or visiting spacecraft. The ISS circles the Earth in roughly 93 minutes, completing orbits per day. | https://en.wikipedia.org/wiki?curid=15043 |
7,194 | The station is divided into two sections: the Russian Orbital Segment (ROS) is operated by Russia, while the United States Orbital Segment (USOS) is run by the United States as well as by the other states. The Russian segment includes six modules. The US segment includes ten modules, whose support services are distributed 76.6% for NASA, 12.8% for JAXA, 8.3% for ESA and 2.3% for CSA. | https://en.wikipedia.org/wiki?curid=15043 |
7,195 | Roscosmos had previously endorsed the continued operation of ROS through 2024, having proposed using elements of the segment to construct a new Russian space station called OPSEK. However, continued cooperation has been rendered uncertain by the 2022 Russian invasion of Ukraine and subsequent international sanctions on Russia, who theoretically, may lower, redirect, or cut funding from their side of the space station due to the sanctions set on them. | https://en.wikipedia.org/wiki?curid=15043 |
7,196 | The first ISS component was launched in 1998, and the first long-term residents arrived on 2 November 2000 after being launched from the Baikonur Cosmodrome on 31 October 2000. The station has since been continuously occupied for , the longest continuous human presence in low Earth orbit, having surpassed the previous record of held by the "Mir" space station. The latest major pressurised module, "Nauka", was fitted in 2021, a little over ten years after the previous major addition, "Leonardo" in 2011. Development and assembly of the station continues, with an experimental inflatable space habitat added in 2016, and several major new Russian elements scheduled for launch starting in 2021. In January 2022, the station's operation authorization was extended to 2030, with funding secured within the United States through that year. There have been calls to privatize ISS operations after that point to pursue future Moon and Mars missions, with former NASA Administrator Jim Bridenstine stating: "given our current budget constraints, if we want to go to the moon and we want to go to Mars, we need to commercialize low Earth orbit and go on to the next step." | https://en.wikipedia.org/wiki?curid=15043 |
7,197 | The ISS consists of pressurised habitation modules, structural trusses, photovoltaic solar arrays, thermal radiators, docking ports, experiment bays and robotic arms. Major ISS modules have been launched by Russian Proton and Soyuz rockets and US Space Shuttles. The station is serviced by a variety of visiting spacecraft: the Russian Soyuz and Progress, the SpaceX Dragon 2, and the Northrop Grumman Space Systems Cygnus, and formerly the European Automated Transfer Vehicle (ATV), the Japanese H-II Transfer Vehicle, and SpaceX Dragon 1. The Dragon spacecraft allows the return of pressurised cargo to Earth, which is used, for example, to repatriate scientific experiments for further analysis. , 251 astronauts, cosmonauts, and space tourists from 20 different nations have visited the space station, many of them multiple times. | https://en.wikipedia.org/wiki?curid=15043 |
7,198 | The ISS was originally intended to be a laboratory, observatory, and factory while providing transportation, maintenance, and a low Earth orbit staging base for possible future missions to the Moon, Mars, and asteroids. However, not all of the uses envisioned in the initial memorandum of understanding between NASA and Roscosmos have been realised. In the 2010 United States National Space Policy, the ISS was given additional roles of serving commercial, diplomatic, and educational purposes. | https://en.wikipedia.org/wiki?curid=15043 |
7,199 | The ISS provides a platform to conduct scientific research, with power, data, cooling, and crew available to support experiments. Small uncrewed spacecraft can also provide platforms for experiments, especially those involving zero gravity and exposure to space, but space stations offer a long-term environment where studies can be performed potentially for decades, combined with ready access by human researchers. | https://en.wikipedia.org/wiki?curid=15043 |
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