Proc Freq for Risk Ratio, 95% CI of Risk Ratio and p-value with method of Chan and Zhang(1999)

[DmytroYermak]

Hi all,

Could you please help with the statistics evaluation.

I need to calculate: Risk Ratio, 95% CI of Risk Ratio and p-value with method of  Chan and Zhang(1999).

Could you please say the syntax of Proc Freq for the case?

Thank you!

[FreelanceReinh · Accepted solution]

Hi @DmytroYermak,

According to the SAS/STAT 14.3 documentation, that method is the new default, so the RELRISK option of the EXACT statement is sufficient:

exact relrisk;

In earlier SAS/STAT versions (up to 14.2) you had to specify

exact relrisk(method=score);

[DmytroYermak]

Thank you! Would you please prompt how to calculate p-value within the procedure as well.

[FreelanceReinh]

There doesn't seem to be an option to compute a corresponding test (although the CI is based on one-sided exact tests). At least I can't find it, sorry. Maybe you can

• iteratively modify the ALPHA= option of the TABLES statement until a pre-specified value equals a confidence limit
• or compute the test outside of PROC FREQ (i.e. manually in a data step -- I don't have code for this)
• or use one of the available tests for the risk difference instead if appropriate.