Increase in power by obtaining 10 or more controls per case when type-1 error is small in large-scale association studies.

ABSTRACT:

Background

The rule of thumb that there is little gain in statistical power by obtaining more than 4 controls per case, is based on type-1 error α = 0.05. However, association studies that evaluate thousands or millions of associations use smaller α and may have access to plentiful controls. We investigate power gains, and reductions in p-values, when increasing well beyond 4 controls per case, for small α.

Methods

We calculate the power, the median expected p-value, and the minimum detectable odds-ratio (OR), as a function of the number of controls/case, as α decreases.

Results

As α decreases, at each ratio of controls per case, the increase in power is larger than for α = 0.05. For α between 10^-6 and 10^-9 (typical for thousands or millions of a

SUBMITTER: Katki HA 

PROVIDER: S-EPMC10308790 | biostudies-literature | 2023 Jun

REPOSITORIES: biostudies-literature