Re: st: St: Dropping variables with mostly missing values

[Jeph Herrin <info@flyingbuttress.net>]

To drop all variables missing more than 80% of the time:

foreach V of varlist _all {
	count if !mi(`V')
	drop if r(N)/_N < 0.2
}


This works for string and numeric variables. Change 0.2 to whatever 
level you want.

hth,
Jeph




On 2/7/2014 3:11 PM, Eric M. Uslaner wrote:
> I know that this has been discussed before, but a long search doesn't find a solution for me (my own fault in searching, most likely).
>
> I have a data set (not my own) with 161 cases over a long time period.  But  most of the variables are largely made up of missing values (information wasn't available a long time ago).  I have used Nick Cox's dropmiss (from SSC) to drop variables with all missing values.  But a large number of variables remain with few observations.  I would like to delete any variable with fewer than 20 cases.  But I can't figure out how to do this (especially since I have a large number of variables, most of which have very few cases).  Any help would be appreciated.
>
> Ric Uslaner
>
>
>
>
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