I guess my problem is a little complex here. I need to specify MISSING VALUES to be able to do IMPUTATION. SoI have a dataset with several variables and each of the variables has missing values, however they are coded in some ways. for example, data one looks like this, vb1 vb2 vb3 1 b 4 1 a 1 2 a 1 3 c 3 2 b 2 actually, in vb1, "1" means missing; in vb2 "a" means messing and in vb3, "4" means missing and so on; Those values means "missing", "unknown", "unspecified", so they are missings just they've been coded. I actually use proc sql to create a new table, and doing something like this, 1. data vb1_index; set one; input value $ value_d $; 1 . 2 1 3 2 ; run; 2. use "proc sql" to combine tables together But in the final results, sas looks at it like vb1 has "no missing values" with "3" (instead of 5) obsetrvations and same as for vb2, vb3...... in this way I have nothing missing since sas only looks at completed cases. I used proc means n nmiss options to get the results. so i don't know if my imputation is going to work well. please let me know a quick way to set those values as missing values because my "several" variables are like.....30+, thank you all very much!!
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