Thank you very much for this post. It is excellent and fits well with my psychometric analysis.
I can not reproduce the calculation of the coefficient of Spearman-Brown:
corr TotalEven TotalOdd
local SBPF = 2 * r (rho) / (1 + r (rho))
disp "The Spearman-Brown Prophesy Reliability Estimate =" as result \% 5.4f 'SBPF'
Stata reports that " \% 5: operator invalid ".
Can you help me?