program define missvar, rclass
*! 1.2 GMH Feb 13 01
local varlist "required existing"
parse "`*'"
parse "`varlist'", p(" ")
quietly count
local n = _result(1)
while "`1'"~="" {
		quietly count if missing(`1')
		if `n'==_result(1) {
			quiet drop `1' 
			local dropped "`dropped' `1'"}
	macro shift
	}
local num: word count `dropped'
if `num' >0 {
	di in gr  "-missvar- dropped " in yel "`num' " in gr "variables"
	}
return local dropped "`dropped'"
return local num "`num'"
end