7.8 Sample size

As GWAS sample size has increased over the years, each larger study is able to discover more variants.

Fig. 7 (source). Increase in GWAS discovery power with sample size.

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Why do we find more associations with larger studies?

1. A larger dataset captures more rare variation
2. A larger dataset provides more statistical power – we can more confidently say whether allele frequencies are different between individuals with and without a phenotype

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