------------------------------------------------------------------------------- help forsvrmean,svrtotal,svrratio-------------------------------------------------------------------------------

Estimate means, totals, ratios, and proportions for survey data,with replication-based standard errors

svrmeanvarlist[ifexp] [inrange] [,common_options]

svrtotalvarlist[ifexp] [inrange] [,common_options]

svrratiovarname[/]varname[varname[/]varname ...] [ifexp] [inrange] [,common_options]

where

common_optionsare

by(varlist)[complete|available]nolabellevel(#)cideffdeftmeffmeftobssize

svrmean,svrratio, andsvrtotaltyped without arguments redisplay previous results. Any of the following options can be used when redisplaying results:

level(#)cideffdeftmeffmeftobssizeThese commands are for use with replication weights. You must set your data for replication based survey estimation with svrset or survwgt before using these commands.

Description

svrmean,svrtotal, andsvrratioproduce estimates of population means, totals, ratios, and proportions. Standard errors are calculated using a series of user-supplied replication weights, by balanced repeated replication (BRR) or the survey jackknife (JK1, JK2, or JKn). This is an alternate method to the Taylor series linearization methods used by Stata's svy commands. See survwgt for details on the creation of weights and estimation of variances with replication.Estimates for multiple subpopulations can be obtained using the

by()option. Theifoption will give estimates for a single population. (Note that with replication methods, use ofiforinproduces correct estimates for the relevant subpopulation; this is not the case with svy commands.)svytest will operate after these commands, as it does after their svy-based equivalents.

Options

by(varlist)specifies that estimates be computed for the subpopulations defined by different values of the variable(s) in thevarlist.

nolabelcan only be specified whenby()is specified.nolabelrequests that numeric values rather than value labels be used to label output for subpopulations. By default, value labels are used.[

complete|available] specifies how missing values are to be handled.completespecifies that only observations with complete data should be used.availablespecifies that all available nonmissing values be used for each estimate.If neither

completenoravailableis specified,availableis the default when there are missing values and there are two or more variables in thevarlist(or four or more forsvyratio).completemust be specified to compute the covariance or to usesvytestafter running the command; see help svytest.

level(#)specifies the confidence level (i.e., nominal coverage rate), in percent, for confidence intervals; see help level.

cirequests that confidence intervals be displayed. If no display options are specified then, by default, confidence intervals are displayed.

deffrequests that the design-effect measure deff be displayed. If no display options are specified then, by default, deff is displayed.

deftrequests that the design-effect measure deft be displayed. See[R]svymeanfor a discussion on deff and deft.

meffrequests that the meff measure of misspecification effects be displayed.

meftrequests that the meft measure of misspecification effects be displayed. See[R] svymeanfor a discussion of meff and meft.

obsrequests that the number of observations used for the computation of the estimate be displayed for each row of estimates.

sizerequests that the estimate of the (sub)population size be displayed for each row of estimates. The (sub)population size estimate equals the sum of the weights for those observations used for the mean/total/ratio estimate.

Examples{inp:. svrmean birthwgt . svrmean birthwgt, by(race) . svrmean birthwgt if race==1

. svrratio hdresult/tcresult

Methods and formulaeSee survwgt.

AcknowledgementsThese commands consists largely of the ado file code from official Stata's

svy_xcommand, which underliessvymean,svytotal, andsvyratio. They are modified to calculate (co)variances differently. I would like to thank Bobby Gutierrez at StataCorp for advice on implementation of BRR.

AuthorNick Winter Cornell University nw53@cornell.edu