Clever New Command for 2x2 Table Values in Stata

A new user-written Stata command, classtabi, generates helpful summary statistics for a standard 2x2 Chi-Square table where only summarized data are available. Values from a 2x2 table can be entered into classtabi to produce the additional classification statistics. To access classtabi, launch Stata and execute "findit" to locate and download the program.

classtabi stores the following in r():
Scalars   
  r(P_corr)    percent correctly classified
  r(P_p1)       sensitivity
  r(P_n0)      specificity
  r(P_p0)      false-positive rate
  r(P_n1)      false-negative rate
  r(P_1p)      positive predictive value
  r(P_0n)     negative predictive value
  r(roc)         ROC curve
  r(ess)         effect strength for sensitivity