title: A cautionary note on the use of simulation procedures for analyzing contingency tables containing small expected cell frequencies.
abstract: A comparison of a simple simulation procedure and exact tests for tables used in psychiatric genetic studies is performed, with focus on tables with small expected cell counts. The study shows that naive simulation procedures using uniform random numbers, could lead to conservative results, as compared with Fisher exact test for contingency tables, thus discarding as non-significant tables that are significant according to the exact test. Exact tests are recommended as an alternative to naive simulation for evaluating the statistical significance of contingency tables with small expected cell counts.
authors.affiliation: Virginia Institute for Psychiatric and Behavioral Genetics, Medical College of Virginia, Virginia Commonwealth University, Richmond, 23298-0126, USA. jrobles@vcu.edu
authors.forename: Jaime R
authors.initials: JR
authors.lastname: Robles
authors.forename: Edwin J C G
authors.initials: EJ
authors.lastname: van den Oord
mesh_terms: D000483:Alleles; D003627:Data Interpretation, Statistical; D005787:Gene Frequency / Q000235:genetics*; D005824:Genetics, Behavioral / Q000379:methods / Q000706:statistics & numerical data; D005838:Genotype; D006801:Humans; D020641:Polymorphism, Single Nucleotide / Q000235:genetics