{smcl}
{hline}
help for {hi:svrtab}
{hline}
{title:One and Two-way tables for survey data, with balance repeated replication (BRR) based standard errors}
{p 4 11}{cmd:svrtab} {it:varname1} [{it:varname2}]
[{cmd:if} {it:exp}] [{cmd:in} {it:range}] [ {cmd:,}
{p 4 4}[tabulate options]
{p 11 11}{cmd:tab(}{it:varname}{cmd:)} {cmdab:miss:ing}
{p 4 4}[display items]
{p 11 11}{cmdab:cel:l} {cmdab:cou:nt} {cmd:row} {cmdab:col:umn} {cmd:obs}
{cmd:se} {cmd:ci} {cmd:deff} {cmd:deft} {cmd:cucol}
{p 4 4}[display formats]
{p 11 11}{c -(} {cmdab:f:ormat(%}{it:fmt}{cmd:)} | {cmdab:fcel:l(%}{it:fmt}{cmd:)}
{cmdab:fcou:nt(%}{it:fmt}{cmd:)} {cmd:frow(%}{it:fmt}{cmd:)} {cmdab:fcol:umn(%}{it:fmt}{cmd:)}
{cmd:fobs(%}{it:fmt}{cmd:)} {cmd:fse(%}{it:fmt}{cmd:)} {cmd:fci(%}{it:fmt}{cmd:)}
{cmd:fdeff(%}{it:fmt}{cmd:)} {cmd:fdeft(%}{it:fmt}{cmd:)} {c )-}
{p 4 4}[display options]
{p 11 11}[ {cmdab:prop:ortion} | {cmdab:per:cent} ] {cmdab:nolab:el}
{cmdab:nomarg:inals} {cmdab:for:mat(%}{it:fmt}{cmd:)} {cmdab:vert:ical}
{cmdab:l:evel(}{it:#}{cmd:)}
{p 4 4}[statistic options]
{p 11 11}{cmdab:pea:rson} {cmd:lr} {cmdab:nul:l} {cmd:wald} {cmd:llwald}
{cmdab:noadj:ust} ]
{p}This command is for use with replication weights. You must set your data for
replication based survey estimation with {help svrset} or {help survwgt} before
using this command.
{p}{cmd:svrtab} typed without arguments redisplays previous results. Any of
the "display items", "display options", or "statistic options" can be
specified when redisplaying with the following exception: {cmd:wald} must be
specified at run time.
{title:Description}
{p}{cmd:svrmodel} produces one- and two-way tabulations with complex survey data.
Tests for independence are available for two-way tables.
Standard errors are calculated using a series of user-supplied
replication weights, by
balanced repeated replication (BRR) or survey jackknife (JK1, JK2, or JKn).
This is an alternate method to the Taylor series linearization methods
used by Stata's {help svy} commands. See {help survwgt} for details on the
creation of weights and estimation of variances with replication.
{p}Except for the different method of variance calculation, {cmd:svrtab}
has identical syntax as {help svytab}. Point estimates are the same
as those from svytab; standard errors and tests of independence are different.
{title:Options regarding Tabulation}
{p 0 0}These options operate exactly as they do in {help svytab}, and this help text
is taken from that help file:
{p 0 4}{cmd:tab(}{it:varname}{cmd:)} specifies that counts should instead be
cell totals of this variable and proportions (or percentages) should be
relative to (i.e., weighted by) this variable. For example, if this variable
denotes income, then the cell "counts" are instead totals of income for each
cell, and the cell proportions are proportions of income for each cell.
{p 0 4}{cmd:missing} specifies that missing values of {it:varname1} and
{it:varname2} are to be treated as another row or column category, rather than
be omitted from the analysis (the default).
{title:Options to Choose Items for Display}
{p 0 0}These options operate exactly as they do in {help svytab}, and this help text
is taken from that help file:
{p 0 4}{cmd:cell} requests that cell proportions (or percentages) be
displayed. This is the default if none of {cmd:count}, {cmd:row}, or
{cmd:column} are specified.
{p 0 4}{cmd:count} requests that weight cell counts be displayed.
{p 0 4}{cmd:row} or {cmd:column} requests that row or column proportions (or
percentages) be displayed.
{p 0 4}{cmd:cucol} requests that cumulative column percentages be displayed.
This option is only valid for tables with one column.
{p 0 4}{cmd:obs} requests that the number of observations for each cell be
displayed.
{p 0 4}{cmd:se} requests that the standard errors of either cell proportions
(the default), weighted counts, or row or column proportions be displayed.
When {cmd:se} (or {cmd:ci}, {cmd:deff}, or {cmd:deft}) is specified, only one
of {cmd:cell}, {cmd:count}, {cmd:row}, or {cmd:column} can be selected. The
standard error computed is the standard error of the one selected.
{p 0 4}{cmd:ci} requests confidence intervals for either cell proportions,
weighted counts, or row or column proportions. The confidence intervals are
constructed using a logit transform so that their endpoints always lie between
0 and 1.
{p 0 4}{cmd:deff} ({cmd:deft}) requests that the design-effect measure deff
(deft) be displayed for either cell proportions, counts, or row or column
proportions. See {hi:[R] svymean} for details. The mean generalized deff is
also displayed when {cmd:deff} or {cmd:deft} is requested.
{title:Options for Display Formats}
{p 0 4}{cmd:format(%}{it:fmt}{cmd:)} specifies an overall format for the items in the
table. The default is {hi:%6.0g}. See
{hi:[U] 15.5 Formats: controlling how data are displayed}.
{p 0 4}Alternately, display formats can be specified separately for the items included
in the table with the other formatting options,
{cmd:fcell()}, {cmd:fcount()}, {cmd:frow()}, {cmd:fcolumn()},
{cmd:fobs()}, {cmd:fse()}, {cmd:fci()}, {cmd:fdeff()}, {cmd:fdeft()}.
{p 4 4}If only one of {cmd:fcell()}, {cmd:fcolumn()}, and {cmd:frow()} is specified, that
format is used for all three, if they are being displayed. Similarly, if only one of {cmd:fdeff()}
and {cmd:fdeft()} is specified, that format will be used for displaying both deff and deft.
{title:Options regarding Display}
{p 0 4}{cmd:proportion} or {cmd:percent} requests that proportions (the
default) or percentages be displayed.
{p 0 4}{cmd:nolabel} requests that variable labels and value labels be
ignored.
{p 0 4}{cmd:nomarginals} requests that row and column marginals not be
displayed.
{p 0 4}{cmd:vertical} requests that the endpoints of the confidence intervals
be stacked vertically on display.
{p 0 4}{cmd:level(}{it:#}{cmd:)} specifies the confidence level (i.e., nominal
coverage rate), in percent, for confidence intervals; see help {help level}.
{p 0 4}{cmd:cellwidth(}{it:#}{cmd:)}, {cmd:csepwidth(}{it:#}{cmd:)}, and
{cmd:stubwidth(}{it:#}{cmd:)} specify widths of table elements in the
output; see help {help tabdisp}.
{p 0 4}{cmd:pearson} requests that the Pearson chi-squared statistic be
computed. By default, this is the test of independence that is displayed.
The Pearson chi-squared statistic is corrected for the survey design using the
second-order correction of Rao and Scott (1984) and converted into an
F-statistic.
{p 4 4}One term in the correction formula can be calculated using either
observed cell proportions or proportions under the null hypothesis (i.e., the
product of the marginals). By default, observed cell proportions are used.
If the {cmd:null} option is selected, then a statistic corrected using
proportions under the null is displayed as well. In most cases, it makes
little difference which is used, but simulations seem to indicate that for
sparse tables, using observed cell proportions is superior.
{p 0 4}{cmd:lr} requests that the likelihood-ratio test statistic for
proportions be computed. Note that this statistic is not defined when there
are one or more zero cells in the table. The statistic is corrected for the
survey design using exactly the same correction procedure that is used with
the {cmd:pearson} statistic. Again, either observed cell proportions or
proportions under the null can be used in the correction formula. By default,
the former is used; specifying the {cmd:null} option gives both the former and
the latter. Neither variant of this statistic is recommended for sparse
tables. For nonsparse tables, the {cmd:lr} statistics are very similar to the
corresponding {cmd:pearson} statistics.
{p 0 4}{cmd:null} modifies the {cmd:pearson} and {cmd:lr} options only. If it
is specified, two corrected statistics are displayed. The statistic labeled
"D-B (null)" ("D-B" stands for design-based) uses proportions under the null
hypothesis (i.e., the product of the marginals) in the Rao and Scott (1984)
correction. The statistic labeled merely "Design-based" uses observed cell
proportions. If {cmd:null} is not specified, only the correction that uses
observed proportions is displayed.
{p 0 4}{cmd:wald} requests a Wald test of whether observed weighted counts
equal the product of the marginals. By default, an adjusted F-statistic is
produced; an unadjusted statistic can be produced by specifying
{cmd:noadjust}. The unadjusted F-statistic can yield extremely
anti-conservative p-values (i.e., p-values that are too small) when the
degrees of freedom of the variance estimates (the number of PSUs minus the
number of strata) are small relative to the (R-1)*(C-1) degrees of freedom of
the table (where R is the number of rows and C is the number of columns).
Hence, the statistic produced by {cmd:wald} and {cmd:noadjust} should not be
used for inference except when it is essentially identical to the adjusted
statistic; it is only made available to duplicate the results of other
software.
{p 0 4}{cmd:llwald} requests a Wald test of the log-linear model of
independence. Note that the statistic is not defined when there are one or
more zero cells in the table. The adjusted statistic (the default) can
produce anti-conservative p-values, especially for sparse tables, when the
degrees of freedom of the variance estimates are small relative to the degrees
of freedom of the table. Specifying {cmd:noadjust} yields a statistic with
more severe problems. Neither the adjusted nor the unadjusted statistic is
recommended for inference; the statistics are only made available for
pedagogical purposes and to duplicate the results of other software.
{p 0 4}{cmd:noadjust} modifies the {cmd:wald} and {cmd:llwald} options only.
It requests that an unadjusted F-statistic be displayed in addition to the
adjusted statistic.
{title:Examples}
{p 8 45}{inp:. svrtab agegrp gender}{p_end}
{p 8 45}{inp:. svrtab, se ci deff} {space 15} [redisplay std. err., etc.]{p_end}
{p 8 45}{inp:. svrtab, count column obs} {space 9} [redisplay counts, etc.]
{p 8 45}{inp:. svrtab agegrp gender, count se} {space 3} [compute std. err. of counts]{p_end}
{p 8 45}{inp:. svrtab, count ci} {space 17} [redisplay CI of counts]
{p 8 45}{inp:. svrtab agegrp gender, wald} {space 7} [compute Wald test]{p_end}
{p 8 45}{inp:. svrtab, pearson lr} {space 15} [redisplay {hi:pearson} and {hi:lr} tests]
{p 8 45}{inp:. svrtab agegrp gender, count se fse(%4.2f) fcount(%4.0fc) }{p_end}
{p 45 45}[specify display formats]{p_end}
{p 8 45}{inp:. svrtab agegrp gender, {bind:tab(income) }} [gives income proportions by {hi:agegrp} and {hi:gender}]
{p 8 45}{inp:. svrtab agegrp, count col } {space 9} [one-dimensional tabulation]
{title:Saved Results}
{cmd:svrtab} generates the same saved results as {cmd:svytab}.
Note that e(cmd) is set to "svytab" in order to allow post-tabulation tests to function correctly.
{title:Methods and formulae}
See {help survwgt}.
{title:Acknowledgements}
{p}{cmd:svrtab} consists largely of the ado file code from official Stata's {cmd:svytab} command, version 1.1.6,
modified to calculate (co)variances differently.
I would like to thank Bobby Gutierrez at StataCorp for advice on implementation of BRR.
{title:Author}
Nick Winter
Cornell University
nw53@cornell.edu