This approach is limited in a number of ways. In particular, the GAD database compares the results of human population based epidemiological studies performed using different sample sizes, populations, statistical models, and at different times over approximately the last 16 years. In addition, the GAD database draws on association studies of broad quality with different degrees of detail provided. Although all human genetic association studies discussed here have been individually determined to be positively associated with a disease or phenotype in a peer reviewed journal, we make no assertion that any individual study is correct and we recognize the controversy in the genetics community regarding statistical and biological significance of genetic association studies. Moreover, although the GAD database contains information on polymorphism and variation, and each GAD record is fundamentally based on polymorphism, this report does not consider variation or polymorphism in the summaries shown. Likewise, mouse genetic models in many cases are weighted to gene knockouts which may not be necessarily be directly representative of multifactorial human common complex disease.