{smcl} {* 18sep2002}{...} {hline} help for {cmd: miset}{right:(SJ3-3: st0000)} {hline} {title:Declare datasets to be multiple imputed datasets} {p 8 27 2} {cmd:miset} [{cmd:using} {it:filename-prefix}] [{cmd:,} {cmdab:m:imps(}{it:#}{cmd:)} {cmd:clear}] {title:Description} {p 4 4 2} {cmd:miset} creates temporary copies of imputed datasets so that subsequent {cmd:mi} (multiple imputation) commands can be executed on these data. The other {cmd:mi} commands can only be used after the multiple datasets have been declared by {cmd:miset}. The imputed datasets are assumed to be created from an original dataset by a "proper" imputation method as in Schafer (1997). These datasets must have the same variables and the same number of observations. {p 4 4 2} The following naming convention must be used: the filenames of the imputed datasets must consist of a common word followed by a consecutive number and followed by the normal extension {cmd:.dta}; for example, {cmd:foo1.dta}, {cmd:foo2.dta}, ..., {cmd:foo5.dta}. Only the common word or {it:filename-prefix} ("foo" in this case) is to be specified after the {cmd:using} command. {p 4 4 2} {cmd:miset} creates temporary files {cmd:mitemp1.dta}, {cmd:mitemp2.dta}, and so on by copying the {cmd:using} files. All subsequent commands will be executed on these temporary files, with the original {cmd:using} files left unchanged. The temporary files remain in the working directory until {help mireset} is issued. To save the updated temporary files after a series of {cmd:mi} commands, see {help misave}. {title:Options} {p 4 8 2} {cmd:mimps(}{it:#}{cmd:)} specifies the number, {it:m}, of datasets to be used. The default is 5. A minimum of 2 and a maximum of 9 datasets can be specified. If there exist more than {it:m} datasets, Only the first {it:m} datasets are used. As mentioned earlier, usually as few as 3 or 5 multiple imputed datasets is sufficient. {p 4 8 2} {cmd:clear} permits the data to be loaded even if there is a dataset already in memory and even if that dataset has changed since the data were last saved. {title:Remarks} {p 4 4 2} {cmd:miset} is one of the suite of {cmd: mi} commands. The other {cmd:mi} commands can only be used after the multiple datasets have been declared by {cmd:miset}. {title:Examples} {p 4 8 2}{cmd:. miset using mydata}{p_end} {p 4 8 2}{cmd:. miset using mydata, mimps(3)} {title:Authors} {p 4 4 2} Ning Li, Philip Greenwood, and John Carlin, Clinical Epidemiology & Biostatistics Unit, Murdoch Children's Research Institute and University of Melbourne. Email {browse "mailto:jbcarlin@unimelb.edu.au":jbcarlin@unimelb.edu.au} {title:References} {p 4 8 2} Rubin, D. B. 1987. {it:Multiple Imputation for Nonresponse in Surveys}. New York: John Wiley & Sons. {p 4 8 2} Schafer, J. L. 1997. {it:Analysis of Incomplete Multivariate Data}. London: Chapman & Hall. {title:Also see} {p 4 14 2}Online: help for {help miappend}, {help mimerge}, {help misave}, {help mido}, {help mici}, {help mifit}, {help milincom}, {help mireset} {p_end}