{smcl} {* *! version 4.07 David Fisher 15sep2023}{...} {vieweralsosee "metan" "help metan"}{...} {vieweralsosee "metan_model" "help metan_model"}{...} {vieweralsosee "metan_binary" "help metan_binary"}{...} {vieweralsosee "metan_continuous" "help metan_continuous"}{...} {vieweralsosee "forestplot" "help forestplot"}{...} {vieweralsosee "metani" "help metani"}{...} {vieweralsosee "" "--"}{...} {vieweralsosee "ipdmetan" "help ipdmetan"}{...} {vieweralsosee "ipdover" "help ipdover"}{...} {vieweralsosee "metabias" "help metabias"}{...} {vieweralsosee "metatrim" "help metatrim"}{...} {vieweralsosee "metaan" "help metaan"}{...} {vieweralsosee "metandi" "help metandi"}{...} {vieweralsosee "metaprop_one" "help metaprop_one"}{...} {hi:help metan_proportion} {hline} {title:Title} {phang} {hi:metan} {hline 2} Perform meta-analysis of single-group proportion data {marker syntax}{...} {title:Syntax} {p 8 18 2} {cmd:metan} {it:n_events} {it:n_total} {ifin} , {opt pr:oportion} [{it:{help metan_model:model_spec}} {it:{help metan_proportion##options:options_proportion}} {it:{help metan##options_main:options_main}}] {marker options_proportion}{...} {synoptset 24 tabbed}{...} {synopthdr :options_proportion} {synoptline} {syntab :Options} {synopt :{opt pr:oportion}}(Required) pool proportions from a single group{p_end} {synopt :{opt cc(#)}}use continuity correction value other than 0.5 for zero cells{p_end} {synopt :{opt nocc}}suppress continuity correction entirely{p_end} {synopt :{opt citype(ci_type)}}method of constructing confidence intervals for reporting of individual studies ({ul:not} pooled results){p_end} {synopt :{opt denom:inator(#)}}specify a denominator for presentation of proportion data{p_end} {synopt :{opt noint:eger}}allow cell counts to be non-integers{p_end} {synopt :{opt tr:ansform(tr_method)}}specify a transformation for analysis of proportion data{p_end} {synopt :{opt nopr}}report effect sizes on transformed scale, not as proportions{p_end} {syntab :Forest plot and/or saved data} {synopt :{opt co:unts}}display data counts ({it:n}/{it:N}){p_end} {synopt :{opt group1(string)}}specify title text for the column created by {opt counts}{p_end} {synoptline} {marker description}{...} {title:Description} {pstd} {cmd:metan} performs meta-analysis of aggregate data; that is, data in which each observation represents a summary of a larger study. This page describes options specific to a meta-analysis of proportions within a single group. Option {opt proportion} {ul:must} be supplied in this context, in order to disambiguate {it:n_events} {it:n_total} from {cmd:metan}'s other two-variable syntax of {it:ES} {it:seES}. {pstd} {help metan:Click here} to return to the main {bf:{help metan}} help page and to find documentation for {it:{help metan_model:model_spec}} and {it:{help metan##options_main:options_main}}. {dlgtab:Options} {phang} {opt cc(#)} controls continuity correction in the case where studies contain zero cells. {pmore} By default, {cmd:metan} adds 0.5 to each cell of a trial where a zero is encountered, to enable finite variance estimators to be calculated. The exception to this is if {cmd:transform(ftukey)} is used; in this case, continuity correction is unnecessary. Note that corrections are applied during computation only; the original data are not modified. However, the {help metan##saved_results:new variable} {cmd:_CC} may be added to the dataset or {help metan##saved_datasets:results set}, to indicate the studies to which a correction was applied. See also the {opt nointeger} option. {pmore} {it:#} is the correction factor. The default is 0.5, but other factors may also be used, including zero. In that case, studies containing zero cells may be excluded from the analysis. {phang} {opt nocc} is synonymous with {cmd:cc(0)} and suppresses continuity correction. Studies containing zero cells may be excluded from the analysis. {phang} {opt citype(ci_type)} specifies how confidence limits for individual studies should be constructed for display purposes. This option acts independently of how confidence limits for {ul:pooled} results are constructed (which will depend upon {it:{help metan_model:model_spec}}). See also {bf:{help metan##options_main:level(#)}} {pmore} For proportion data, the default {it:ci_type} is {opt wilson}, but can also be {opt exact} (a.k.a. Clopper-Pearson), or any of the alternatives listed under {bf:{help ci}} for proportions. If option {opt transform()} is specified, {it:ci_type} may also be {opt transform}, meaning that individual study confidence limits should be derived via back-transformation as well as the pooled estimate. {phang2} If {opt nointeger} is specified, a Wald-type interval will be constructed and {opt citype()} may not be specified. {phang} {opt denominator(#)} specifies a denominator for presenting proportion data, with a default value of 1. For example, specifying {cmd:denominator(100)} would present the data as percentages between 0 and 100. Specifying {cmd:denominator(1000)} would present the data as the number of events per 1000 observations. Note that this option has no effect upon the analysis; it simply scales the results. {phang} {opt nointeger} allows cell counts or sample sizes to be non-integers. {phang} {opt transform(tr_method)} specifies a method of transforming proportion data to create a distribution closer to normality and to stabilise variances. The following transformations are available using {it:tr_method}: {pmore} {opt logit} specifies the Logit transform. Estimates and variances are undefined if the proportion is zero or one, so by default a continuity correction of 0.5 is applied; see {opt cc()} {pmore} {opt ar:csine} specifies the Arcsine transform, for which continuity correction is not required. {pmore} {opt ft:ukey} specifies the Freeman-Tukey double-arcsine transform. Again, continuity correction is not required. {help metan##refs:Schwarzer et al (2019)} show that the standard back-transformation using the harmonic mean can sometimes give misleading results. Hence, sensitivity analyses may be carried out using the extended syntax {cmd:transform(}{opt ft:ukey} [{cmd:, }{opt a:rithmetic}|{opt g:eometric}]{cmd:)} to specify an alternative mean. {help metan##refs:Barendregt et al (2013)} suggest another alternative back-transformation based on the inverse-variance of the pooled transformed effects, which may be specified using {cmd:transform(}{opt ft:ukey}{cmd:, }{opt iv:ariance}{cmd:)}. {phang} {opt nopr} requests that effect sizes are reported on the transformed scale. In other words, back-transformation to the proportion scale is not performed. {dlgtab:Forest plot and/or saved data} {phang} {opt counts} displays data counts {it:n}/{it:N} for each group in columns to the left of the forest plot. {pmore} {opt group1(string)} specifies a column heading for the {opt counts} column. {title:Authors} {pstd} Original authors: Michael J Bradburn, Jonathan J Deeks, Douglas G Altman. Centre for Statistics in Medicine, University of Oxford, Oxford, UK {pstd} {cmd:metan} v3.04 for Stata v9: Ross J Harris, Roger M Harbord, Jonathan A C Sterne. Department of Social Medicine, University of Bristol, Bristol, UK {pstd} {cmd:metan} v4.00 and later (including current version): David Fisher, MRC Clinical Trials Unit at UCL, London, UK. {pstd} Email {browse "mailto:d.fisher@ucl.ac.uk":d.fisher@ucl.ac.uk} {title:Acknowledgments} {pstd} Thanks to Patrick Royston (MRC Clinical Trials Unit at UCL, London, UK) for suggestions of improvements to the code and help file. {pstd} Thanks to Vince Wiggins, Kit Baum and Jeff Pitblado of Statacorp who offered advice and helped facilitate the version 9 update. {pstd} Thanks to Julian Higgins and Jonathan A C Sterne (University of Bristol, Bristol, UK) who offered advice and helped facilitate this latest update, and thanks to Daniel Klein (Universit{c a:}t Kassel, Germany) for assistance with testing under older Stata versions. {pstd} The "click to run" element of the examples in this document is handled using an idea originally developed by Robert Picard. {marker refs}{...} {title:References} {phang} Barendregt JJ, Doi SA, Lee YY, Norman RE, Vos T. 2013. Meta-analysis of prevalence. J Epidemiol Community Health 67: 974–978. doi:10.1136/jech-2013-203104 {phang} Schwarzer G, Chemaitelly H, Abu-Raddad LJ, R{c u:}cker G. 2019. Seriously misleading results using inverse of Freeman-Tukey double arcsine transformation in meta-analysis of single proportions. Research Synthesis Methods 10: 476–483. doi: 10.1002/jrsm.1348