*! version 1.0 30Nov2005 Joseph Hilbe * CENSORED NEGATIVE BINOMIAL REGRESSION : LOG-LIKELIHOOD FUNCTION : HILBE SURVIVAL PARAMETERIZATION program cenegbinll version 9.1 args lnf xb alpha tempvar a mu local censor "$S_cen" qui gen double `a' = exp(`alpha') qui gen double `mu' = exp(`xb') * `a' qui replace `lnf' = cond(`censor' == 1, $ML_y1 * ln(`mu'/(1+`mu')) - /// ln(1+`mu')/`a' + lngamma($ML_y1 + 1/`a') - /// lngamma($ML_y1 + 1) - lngamma(1/`a'), ln(gammap($ML_y1, exp(`xb'))), /// ln(ibeta($ML_y1, $S_obs - $ML_y1 +1, exp(`xb'))) ) qui replace `lnf' = ln(ibeta($ML_y1+1, $S_obs - $ML_y1, exp(`xb'))) if `censor' == -1 end