help wfmissing

Title

Working with missing data

List of examples

Select cases if variables are not missing.

Commands for missing values.

Summarize missing data in dataset.

Suggested meanings for extended missing values.

Select cases if variables are not missing

mark notmissing // create variable to indicate if not missing
markout notmissing var1 var2 ... varK // check these variables
label def notmissing 0 0_missing 1 1_nomiss
label val notmissing notmissing
tab notmissing, missing
keep if notmissing

Commands for missing values

Select if missing

keep if missing(myvar)

Select if not missing

keep if !missing(myvar)

Select if not missing}

keep if !missing(myvar)

Indicate of missing for any of a set of variables}

gen ismiss = miss(var1,var2,var3)

Summarize missing data in dataset

misschk

For details, help misschk. misshck is part of the
SPOST package.

Suggested meanings for extended missing values

Letter Used for
. Sysmiss; unspecified reason for missing data.

.d Don't know.

.l Do not use since easy to confuse with 1 (one).

.n Not applicable, such as only adults were asked question.

.p Preliminary (i.e., lead in) question refused.

.r Refused to answer.

.s Skipped due to skip pattern.

.t Technical problem such as read error on mark sense form.

Also see

wf