First, use proportions rather than percentages. What you have an an estimate for the ratio of two proportions. What you want is called the confidence interval for the ratio.   One way to do this is to log-transform the ratio, use a standard equation to find the confidence interval, and then exponentiate to transform back. Look up the section of the PROC FREQ doc about odds ratios and relative risks for 2x2 tables. The section "Confidence Limits for the Odds Ratio" explains the math.   If this is what you are looking for, then I suggest you post sample data for 3 or 4 studies. (The data can be fake.) Someone ought to be able to show you how to get the data from the format you have into a format that PROC FREQ requires for analysis. ... View more