d Stata Journal volume 3, issue 1 t .. Other Stata Journals p st0030 Instrumental variables and GMM: Estimation and testing p st0031 Intraclass correlation in random-effects models for p - binary data p st0032 Sample size calculations for main effects and p - interactions in case-control studies using Stata's nchi2 p - and npnchi2 functions p st0033 Implementing tests with correct size in the simultaneous p - equations model