An evaluation of the variance components approach: Type I error, power and size of the estimated effect

Yin Yao Shugart, Jeffrey R. O'Connell, Alexander F. Wilson

Research output: Contribution to journalArticle


In order to evaluate the statistical properties of the variance components method implemented in SOLAR and GENEHUNTER2, the type I error rate, power and estimated size of modelled effects were determined using computer simulation. Results suggested that the type I error rate was quite conservative when the variance was completely due to random effects. However, when either a polygenic effect or an unlinked single locus component effect was included in the generating models the type I error rate was closer to the nominal level. The size of the polygenic or single locus effect appeared to influence the type I error rate. Results suggested that the variance components method underestimated the variance attributed to a single locus effect and overestimated the variance attributed to a polygenic effect in the models considered regardless of the source of variation.

Original languageEnglish (US)
Pages (from-to)133-136
Number of pages4
JournalEuropean Journal of Human Genetics
Issue number2
StatePublished - 2002



  • Power
  • Simulation
  • Type I error
  • Variance components approach

ASJC Scopus subject areas

  • Genetics(clinical)

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