Notice: On April 23, 2014, Statalist moved from an email list to a forum, based at statalist.org.
From | Steve Samuels <sjsamuels@gmail.com> |
To | statalist@hsphsun2.harvard.edu |
Subject | Re: st: Bootstrapping in svy with vce(linearized) |
Date | Thu, 12 Apr 2012 18:03:59 -0400 |
Rini Rao: Look at the results of -svy: regress- again; they state the reason for the missing standard errors; it has little to do with sample size. Also re-read the -help- for -svyset- about the consequences of choosing the singleunit(missing) option. Choose a different one; I suggest "centered" as the most conservative. And, as Stas pointed out, you must incorporate your -if- clause into the subpop() definition. Steve sjsamuels@gmail.com On Apr 12, 2012, at 2:18 PM, Rini Rao wrote: Hello fellow Stata folks, I am using the NHANES data with the svy command and vce(linearized). For my analysis, I have created subgroups based on certain parameters for complete data. e.g (s_white_1840) For certain subgroups, I have ended up with very small sample sizes (e.g. n=353) and in some cases I only get a model co-efficient estimate without accompanying standard errors. e.g. . svyset psu [pweight=wtsaf], strata(strata) vce(linearized) singleunit(missing) . xi: svy, sub(s_gaby_diab_1318): regress egfr abdobes if homa_1318<4 & htn==0 (running regress on estimation sample) Survey: Linear regression Number of strata = 74 Number of obs = 1544 Number of PSUs = 148 Population size = 6726762.5 Subpop. no. of obs = 1544 Subpop. size = 6726762.5 Design df = 74 F( 0, 74) = . Prob > F = . R-squared = 0.0029 ------------------------------------------------------------------------------ | Linearized egfr | Coef. Std. Err. t P>|t| [95% Conf. Interval] -------------+---------------------------------------------------------------- abdobes | 3.147383 . . . . . _cons | 92.33331 . . . . . ------------------------------------------------------------------------------ Note: missing standard errors because of stratum with single sampling unit. Now, how can I obtain unbiased S.E. and confidence intervals for this estimate. Is it acceptable to run a bootstrap using this command? (I get a reasonable output using this command but I don't know if it makes sense to use this). bootstrap _b _se if homa_1318<4 & fabg<100 & htn==0, reps(1000) strata(s_gaby_diab_1318) seed(89) : regress egfr abdobes Harini Sarathy. * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/ * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/