If we are trying to find the power of a paired t-test, SAS offers this template (among others) in
proc power; pairedmeans test=diff meandiff = 7 corr = 0.4 stddev = 12 npairs = 50 power = .; run;
R, on the other hand, has this:
pwr.t.test(n = NULL, d = NULL, sig.level = 0.05, power = NULL, type = c("two.sample", "one.sample", "paired"), alternative = c("two.sided", "less", "greater"))
where there is no way to specify the correlation. But the correlation makes a huge difference to the results. d (the effect size) is Cohen's d (difference in the means divided by pooled standard deviation).
Is this an error in the R program (that seems very unlikely) or have I missed something (far more likely) and, if I have missed something, what is it I have missed?