Pls see attachment of SAS code, suppose I have zero responder in strata 2 then "proc freq" unable to provide Newcombe confidence limit with note that, " NOTE: Newcombe confidence limits for the common risk difference cannot be computed for this table (Treatment by Responder controlling for startum) due to zero-frequency rows, columns, or cells." However if I use that macro then I gets values for CI for Newcombe . Please help why it is happening from SAS, why SAS is giving results, it is due to CI is not reliable even it is calculable ?

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