everyone I am new here and I need some help. I keep encountering this error: proc surveylogistic data=nhis29; cluster ppsu; strata pstrat; weight wtfa; class SRVY_YR(ref='2021') edu(ref='1') pov(ref='1') sex(ref='1')/param=ref; model ft=srvy_yr edu pov sex/expb; run; ERROR: Invalid reference value for SRVY_YR. Yet for the same variable and reference everything seems fine as shown below: proc surveylogistic data=nhis29; cluster ppsu; strata pstrat; weight wtfa; class SRVY_YR(ref='2021')/param=ref; model ft(event='1')=srvy_yr/expb; run; NOTE: PROC SURVEYLOGISTIC is modeling the probability that ft=1. NOTE: Convergence criterion (GCONV=1E-8) satisfied. NOTE: PROCEDURE SURVEYLOGISTIC used (Total process time): real time 0.20 seconds cpu time 0.11 seconds I can't think of what I missed, and any assistance would be appreciated I tried proc surveyfreq and 2021 is a category and works fine ... View more