# Margins of Error in SAS

I’m trying to accurately calculate margins of error at the 90% confidence level using ACS data in SAS.

My code (which also includes chi square) looks like this, and is working great.

PROC surveyfreq DATA=data1 VARMETHOD=JACKKNIFE;
WEIGHT perwt;
REPWEIGHT repwtp1-repwtp80/JKCOEFS=0.05;
tables variable1*(variable2)/ expected row col chisq lrchisq wchisq wllchisq CLWT CL ALPHA = 0.1;
RUN;

Question: There are two ways I’ve calculated the MOE, and results differ. If I multiply the resulting standard error by 1.645, I get a slightly different result than if I subtract an estimate from its upper limit. I think I’m confusing myself or missing something, but shouldn’t these be the same? If not, which one would be the correct one drawing on the jackknife/replicate weight method?

Percent | 4.132
Std Err ofPercent | 0.085
90% Confidence Limits for Percent | 3.991, 4.274

MOE= 1.645*0.085 = 0.1397
MOE= 4.274 - 4.132 = 0.1414

Thank you!

Both of the methods you have used should give you the Margin of Error. I believe you are getting conflicting results because you are rounding your numbers to too few significant digits. Try your calculations with several more significant digits to see if the results compare.