<div dir="ltr"><div>i suspect i'm belaboring the obvious here, but here's how SAS treats numeric missings</div>SAS numeric missings appear to be "character strings" - but they are treated, within SAS (and Stata i believe) as "invented" numbers, smaller than the "smallest" negative number. eg -1*10**10000 > .z > .a > . > ._ ; (though i don't think i've ever seen "._" used). However their great virtues are: 1. As "known" missings they automatically get excluded from computations involving the variable they represent. And, like any other value (character or numeric) the can be described using formats.. That is when you do, say, a frequency proc and assign formats to the missing you'd see something like:<div>
time_to_pregnancy1</div><div>value timetopg </div><div> 1-2 = '1-2 mos'</div><div> 3-5 = '3-5 mos'</div><div> 6-12 = '6-12 mos'</div><div> 13-high = ' > 1 yr'</div><div> .r = 'Refused'</div>
<div> .d = "don't remember"</div><div> .m = 'set to missing by rule'</div><div>. = 'other missing'</div><div>;</div><div>Value labels are the equivalent SPSS feature (i think..i haven't used SPSS in 35 yrs) and even now most of our original questionnaires use "out of range" numbers for special missing values. But the number of times post-docs and researchers have come up with funky basic descriptive statistics because, oh, "99" was used for a missing value for "height_inches" is well nigh uncountable. And matters are getting worse because there's a general tendency to not use codebooks any more; instead projects rely on "annotated questionnaires" and SAS "proc contents" I am very much hoping to get people here to go back to using codebooks and the various DDI products SHOULD be convincing. (well, convincing for people other than the small group of reproductive epidemiology researchers I work with most closely).</div>
<div><br></div><div>thanks for the responses!</div><div><span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:12.666666984558105px;background-color:rgb(255,255,255)">Bob McC....</span><br style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:12.666666984558105px;background-color:rgb(255,255,255)">
<br style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:12.666666984558105px;background-color:rgb(255,255,255)"><span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:12.666666984558105px;background-color:rgb(255,255,255)">"At times like this, an adult needs a drink."</span><br style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:12.666666984558105px;background-color:rgb(255,255,255)">
<span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:12.666666984558105px;background-color:rgb(255,255,255)">Dance, Dance, Dance. H. Murakami</span>
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