. tab h11
had diarrhea |
recently | Freq. Percent Cum.
--------------------+-----------------------------------
no | 8,826 88.21 88.21
yes, last two weeks | 1,090 10.89 99.10
don't know | 90 0.90 100.00
--------------------+-----------------------------------
Total | 10,006 100.00
"tab h11,m" will show that there were 635 NA cases. All of the NA cases are children born in the past 5 years who died before the survey. Clearly they should be omitted from both the numerator and the denominator. The denominator for the proportion would include all 10,006 cases, but the numerator would only include the "yes" responses. The "don't know" responses are in effect grouped with "no". The reason for grouping them with "no", as I think of it, is to avoid over-estimating the prevalence of the outcome. There could be other variables in which "don't know" would be grouped with "yes", but for the same reason, that we want to be conservative and avoid over-estimating the prevalence of an unfavorable outcome.
. tab h11
had diarrhea |
recently | Freq. Percent Cum.
--------------------+-----------------------------------
no | 9,068 83.90 83.90
yes, last two weeks | 1,620 14.99 98.89
don't know | 105 0.97 99.86
9 | 15 0.14 100.00
--------------------+-----------------------------------
Total | 10,808 100.00