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README.md

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----
-license: other
-license_name: embl-ebi
-license_link: https://www.ebi.ac.uk/about/terms-of-use/
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+---
+license: other
+license_name: embl-ebi
+license_link: https://www.ebi.ac.uk/about/terms-of-use/
+---
+
+# GWAS Catalog Samples
+
+## Dataset Description
+
+This dataset contains sample-level metadata from the [NHGRI-EBI GWAS Catalog](https://ebi.ac.uk/gwas), describing the populations included in genome-wide association studies (GWAS).
+
+Each record represents a population sample used within a GWAS study, including information about sample size, ancestry category, and geographic origin. The dataset provides a structured representation of the participant populations contributing to published GWAS results.
+
+Unlike the [GWAS Catalog Studies dataset](https://huggingface.co/datasets/gwascatalog/studies), which focuses on publication-level metadata, and the [Associations dataset](https://huggingface.co/datasets/gwascatalog/associations), which captures SNP–trait associations, the Samples dataset describes the populations and cohorts contributing to GWAS analyses.
+
+This dataset is particularly valuable for understanding genetic ancestry representation in GWAS research, enabling analyses of population diversity, recruitment geography, and ancestry distribution across studies.
+
+Typical research uses include:
+
+* examining ancestry representation in GWAS cohorts
+* analysing geographic recruitment patterns in genomic studies
+* studying population diversity across GWAS datasets
+* assessing ancestry imbalance or underrepresentation in genetic studies
+* linking population metadata with study-level and association-level GWAS data
+
+The GWAS Catalog applies a standardised framework for representing ancestry data in genomics studies. For more details, please see:
+
+Morales, J., Welter, D., Bowler, E.H. et al. A standardized framework for representation of ancestry data in genomics studies, with application to the NHGRI-EBI GWAS Catalog. Genome Biol 19, 21 (2018). https://doi.org/10.1186/s13059-018-1396-2
+
+---
+
+## Dataset Summary
+
+* Task categories: genomics, biomedical metadata analysis
+* Data type: tabular
+* Primary domain: genome-wide association studies (GWAS)
+* Unit of observation: GWAS sample population
+* Source: curated literature database
+
+Typical uses include:
+
+* analysing ancestry composition of GWAS cohorts
+* evaluating population diversity in genomic research
+* linking ancestry metadata with GWAS study results
+* studying recruitment geography and sampling strategies in GWAS
+
+---
+
+# Dataset Structure
+
+Each row represents a specific sample population used in a GWAS study, typically corresponding to either the discovery stage or a replication stage cohort.
+
+A single study may contain multiple sample entries representing different cohorts, recruitment locations, or ancestry groups.
+
+## Columns
+
+| Column                          | Description                                                                                                     |
+| ------------------------------- | --------------------------------------------------------------------------------------------------------------- |
+| STUDY ACCESSION                 | Accession identifier assigned to a GWAS study in the GWAS Catalog (e.g., GCST identifiers).                     |
+| PUBMEDID                        | PubMed identifier for the publication reporting the GWAS.                                                       |
+| FIRST AUTHOR                    | Last name and initials of the first author of the publication.                                                  |
+| DATE                            | Publication date (online/epub date if available).                                                               |
+| INITIAL SAMPLE DESCRIPTION      | Description of the discovery-stage GWAS cohort, including sample size and ancestry information.                 |
+| REPLICATION SAMPLE DESCRIPTION  | Description of replication cohort(s) used to validate associations reported in the study.                       |
+| STAGE                           | Stage of the GWAS to which the sample description applies (e.g., initial discovery stage or replication stage). |
+| NUMBER OF INDIVIDUALS           | Number of individuals included in the sample population.                                                        |
+| BROAD ANCESTRAL CATEGORY        | High-level ancestry classification assigned to place samples into broader genetic ancestry groups.              |
+| COUNTRY OF ORIGIN               | Country associated with the ancestral origin of the individuals in the sample.                                  |
+| COUNTRY OF RECRUITMENT          | Country where participants were recruited for the study.                                                        |
+| ADDITIONAL ANCESTRY DESCRIPTION | Additional descriptors providing more detailed ancestry information for the sample population.                  |
+
+---
+
+# Curation Process
+
+The GWAS Catalog is curated through a combination of automated and manual processes.
+
+### 1. Literature identification
+
+Publications describing genome-wide association studies are identified through:
+
+* literature searches
+* author submissions
+
+### 2. Manual curation
+
+Expert curators review publications and extract key information including:
+
+* variant identifiers (e.g., rsIDs)
+* associated traits or diseases
+* statistical significance metrics
+* effect sizes
+* sample descriptions
+* genomic location information
+
+### 3. Standardisation
+
+Extracted data are normalised using standardised vocabularies and identifiers where possible, including:
+
+* controlled trait terms from the [Experimental Factor Ontology (EFO)](https://www.ebi.ac.uk/efo/)
+* genomic coordinates
+* gene identifiers
+
+### 4. Annotation
+
+Variants are annotated with additional genomic information such as:
+
+* mapped genes
+* variant context (e.g., intronic, intergenic)
+* genomic distances to nearby genes
+
+### 5. Quality control
+
+Curated records undergo internal quality checks to ensure:
+
+* consistency across records
+* correct variant identifiers
+* valid genomic annotations
+
+For more information about the curation process, please see the [GWAS Catalog documentation](https://ebi.ac.uk/gwas/docs/methods).
+
+The Hugging Face dataset mirrors the [tabular ancestry records published by the GWAS Catalog on 2026-03-17](https://www.ebi.ac.uk/gwas/docs/file-downloads).
+
+---
+
+# Bias, Limitations, and Population Representation
+
+Genome-wide association studies have several limitations that affect analyses using this dataset.
+
+## Population Bias
+
+A large proportion of GWAS studies have historically been conducted with individuals genetically similar to European reference populations.
+
+Please note:
+
+* genetic associations may not generalise across populations
+* allele frequencies may differ substantially between ancestries
+* effect sizes may vary across populations
+
+Users should exercise caution when applying results derived from GWAS to diverse populations.
+
+## Publication Bias
+
+Because the catalog is derived from published studies, it may reflect:
+
+* overrepresentation of statistically significant findings
+* underrepresentation of null results
+* bias towards traits that are frequently studied
+
+## Study Heterogeneity
+
+GWAS studies vary substantially in:
+
+* sample size
+* cohort composition
+* phenotype definitions
+* genotyping platforms
+* statistical analysis methods
+
+These factors may influence comparability across studies.
+
+---
+
+# Credits
+
+This dataset is derived from the [NHGRI-EBI GWAS Catalog](https://ebi.ac.uk/gwas).
+
+We would like to thank:
+
+* authors who submit their data to the catalog, including full summary statistics
+* authors of the original GWAS publications included in the catalog
+* GWAS Catalog team members, past and present
+* research participants who contributed data to the underlying genetic studies
+
+---
+
+# Citation
+
+If you use this dataset in research, please cite the GWAS Catalog publication:
+
+Maria Cerezo et al.
+*The NHGRI-EBI GWAS Catalog: standards for reusability, sustainability and diversity.*
+Nucleic Acids Research, 2025.
+
+```bibtex
+@article{cerezo2025nhgri,
+  title={The NHGRI-EBI GWAS Catalog: standards for reusability, sustainability and diversity},
+  author={Cerezo, Maria and Sollis, Elliot and Ji, Yue and Lewis, Elizabeth and Abid, Ala and Bircan, Karatu{\u{g}} Ozan and Hall, Peggy and Hayhurst, James and John, Sajo and Mosaku, Abayomi and others},
+  journal={Nucleic acids research},
+  volume={53},
+  number={D1},
+  pages={D998--D1005},
+  year={2025},
+  publisher={Oxford University Press}
+}
+```
+
+---
+
+# Licence
+
+The NHGRI-EBI GWAS Catalog and all its contents are available under the [general Terms of Use for EMBL-EBI Services](https://ebi.ac.uk/about/terms-of-use). Summary statistics are made available under CC0 unless otherwise stated.
+
+Consumers of data hosted by the GWAS Catalog should review the licence terms of individual datasets where applicable to their specific use case.