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


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