..- help for ^marker^ ..- Mark sample with all values present for later use ------------------------------------------------- ^marker^ [varlist] [weight] [^if^ exp] [^in^ range] [^,^ ^g^en^(^markvar^)^ ^st^rok] Description ----------- ^marker^ creates a 0-1 variable markvar, such that markvar has value 1 if all values are present (not missing) for every variable in varlist and have sensible non-zero weights if weights are specified and satisfy any ^if^ or ^in^ condition specified and 0 otherwise. The name of markvar defaults to ^_marker^, providing that is not already in use. The main use of ^marker^ is to define samples so that the results of commands that automatically ignore any observations with missing values on any of the variables specified (e.g. ^regress^) are comparable with the results of other commands that do not do this (e.g. ^summarize^). Once the sample has been defined, it can be specified by ... ^if ^markvar^ == 1^ or even more concisely by ... ^if ^markvar Options ------- ^gen(^markvar^)^ specifies the name of a new variable for markvar. ^strok^ indicates that non-missing string values (i.e. values other than the empty string "") are acceptable for any string variables in varlist as defining present observations. Examples -------- . ^marker rep78^ . ^su if _marker^ . ^regress a b c d e^ . ^marker a b c d e, g(regdata)^ . ^su if regdata^ Author ------ Nicholas J. Cox, University of Durham n.j.cox@@durham.ac.uk Also see: -------- On-line: help for @mark@ Manual: [R] mark