Stata is a complete, integrated statistical package that provides everything you need for data analysis, data management, and graphics. Stata is not sold in modules, which means you get everything you need in one package. And, you can choose a perpetual license, with nothing more to buy ever. Annual licenses are also available.Stata 12 adds many new features such as structural equation modeling (SEM), contrasts, ARFIMA, business calendars, chained equations for multiple imputation, contour plots, automatic memory management, importing and exporting of Excel files, and more. (Source: