| { | |
| "original_study": { | |
| "claim": { | |
| "hypothesis": "Higher average weekly working hours at the U.S. state level will be associated with higher carbon dioxide emissions from fossil fuel combustion.", | |
| "hypothesis_location": "Introduction and Literature review, which motivate examining the relationship between working hours and emissions (pages 1–3).", | |
| "statement": "The study finds that, over time, a 1 percent increase in average working hours per worker in a state is associated with a 0.668 percent increase in state-level CO2 emissions from fossil fuel combustion, net of other political, economic, and demographic drivers of emissions.", | |
| "statement_location": "Results section and Table 4 (page 16).", | |
| "study_type": "Observational." | |
| }, | |
| "data": { | |
| "source": "State-level carbon dioxide emissions from fossil fuel combustion from the U.S. Environmental Protection Agency (EPA), working hours and labor statistics from the U.S. Bureau of Labor Statistics Current Employment Statistics (CES), GDP and manufacturing share from the U.S. Bureau of Economic Analysis, energy production from the U.S. Energy Information Administration’s State Energy Data System, and demographic variables (population, household size, working-age share) from the U.S. Census Bureau and American Community Survey. State environmentalism scores come from Dietz et al. (2015).", | |
| "wave_or_subset": "Annual state-level data for all 50 U.S. states from 2007 to 2013, forming a balanced panel.", | |
| "sample_size": "350 state-year observations (50 states observed annually over 7 years, 2007–2013).", | |
| "unit_of_analysis": "State-year.", | |
| "access_details": "The authors note that the EPA state CO2 emissions files were obtained from an earlier snapshot of the EPA website and that the lead author will share these data upon request; other data sources (BLS, BEA, EIA, Census, ACS) are described as coming from publicly available databases.", | |
| "notes": "All non-binary variables are log-transformed. The dependent variable is total state-level CO2 emissions from fossil fuel combustion in million metric tons. Average weekly working hours are for nonfarm private employees only." | |
| }, | |
| "method": { | |
| "description": "The authors construct a balanced panel of the 50 U.S. states from 2007 to 2013 and estimate fixed-effects, random-effects, and hybrid panel regression models to assess whether average weekly working hours per worker are positively associated with state-level carbon dioxide emissions from fossil fuel combustion, net of economic, demographic, political, and energy-related controls.", | |
| "steps": [ | |
| "Assemble annual state-level data for all 50 U.S. states from 2007 to 2013, including CO2 emissions from fossil fuel combustion, average weekly working hours per worker, GDP per capita, GDP per hour, employment-to-population ratio, population, manufacturing share of GDP, state energy production, average household size, working-age population percentage, state environmentalism scores, and census region.", | |
| "Log-transform all non-binary variables so that coefficients can be interpreted as elasticities (percent changes).", | |
| "Specify panel regression models with total CO2 emissions (logged) as the dependent variable and average weekly working hours (logged) as the main independent variable.", | |
| "Estimate two-way fixed-effects Prais–Winsten models with AR(1) corrections, including state-specific and year-specific intercepts, to assess the scale effect of working hours (models that also include GDP per hour and employed population percentage) and the composition effect (models that include GDP per capita instead of its components).", | |
| "Estimate random-effects panel models with year-specific intercepts, AR(1) correction, state environmentalism, and census-region dummy variables as additional controls to assess robustness.", | |
| "Conduct robustness checks using hybrid models that include both unit-specific means and deviations for time-varying covariates, and sensitivity analyses excluding one state at a time and excluding states experiencing recent fracking booms.", | |
| "Interpret the elasticity coefficient for logged average working hours as the percent change in CO2 emissions associated with a 1 percent change in working hours, net of controls." | |
| ], | |
| "models": "Two-way fixed-effects panel regression models with Prais–Winsten estimation and AR(1) correction; random-effects panel regression models with AR(1) correction; and hybrid models that decompose time-varying covariates into unit-specific means and deviations.", | |
| "outcome_variable": "Log of total state-level carbon dioxide emissions from fossil fuel combustion (million metric tons CO2).", | |
| "independent_variables": "Log of average weekly working hours per worker in each state.", | |
| "control_variables": "Log GDP per hour; log employed population percentage; log GDP per capita (in composition-effect models); log total population; log state energy production; log manufacturing as a percentage of GDP; log average household size; log working-age population percentage (15–64); state environmentalism index; and census region dummy variables (Midwest, South, West, with Northeast as the reference category), along with state and year fixed effects in the fixed-effects models.", | |
| "tools_software": "Stata (Version 13)." | |
| }, | |
| "results": { | |
| "summary": "Across fixed-effects, random-effects, and hybrid panel models, average weekly working hours are positively and significantly associated with state-level CO2 emissions from fossil fuel combustion. In the preferred fixed-effects scale model, a 1 percent increase in average working hours per worker is associated with a 0.668 percent increase in emissions, net of productivity, employment, population, energy production, manufacturing share, household size, and working-age population. Similar positive and significant elasticities are found in other model specifications, supporting the conclusion that longer working hours contribute to higher emissions at the state level.", | |
| "numerical_results": [ | |
| { | |
| "outcome_name": "Log total CO2 emissions from fossil fuel combustion (elasticity with respect to average weekly working hours, fixed-effects scale model)", | |
| "value": 0.668, | |
| "unit": "elasticity coefficient (percent change in CO2 emissions associated with a 1 percent increase in average weekly working hours)", | |
| "effect_size": "panel regression elasticity coefficient = 0.668 (model 1)", | |
| "confidence_interval": { | |
| "lower": "not stated", | |
| "upper": "not stated", | |
| "level": "not stated" | |
| }, | |
| "p_value": "< 0.001", | |
| "statistical_significance": 1, | |
| "direction": "positive" | |
| } | |
| ] | |
| }, | |
| "metadata": { | |
| "original_paper_id": "10.1093/sf/soy014", | |
| "original_paper_title": "Working Hours and Carbon Dioxide Emissions in the United States, 2007–2013", | |
| "original_paper_code": "not stated", | |
| "original_paper_data": "not stated" | |
| } | |
| } | |
| } |