capture program drop lognormal_lefttrunc program lognormal_lefttrunc version 12 args lnfj mu var tempvar A B C quietly { gen double `A' = normal((log($ML_y2) - `mu')/`var') gen double `B' = ((2*_pi)^(1/2))*`var'*$ML_y1 gen double `C' = (((log($ML_y1)-`mu')/`var')^2)/2 replace `lnfj' = -ln(1-`A') - `C' -ln(`B') } end