Selectivity:

Please note that all selectivity rankings regardless of source or party that evaluates an institution is subjective and should be considered very carefully and with critically. The selectivity information presented here is based on Barron's selectivity rankings over several years. We highly recommend that for purpose of getting the most accurate idea about college selectivity you also consult other selectivity rankings conducted by USNEWS, BusinessWeek, the Financial Times, etc. Also, it'd prudent to acquire a print resource (i.e. Barons Profiles of American Colleges - it also provides selectivity levels) - this might allow you to get even better idea about the selectivity rankings as it lists the formulas used to calculate selectivity.

Understanding college selectivity:

A good article on University Selectivity rankings has been provided on the College Data's website. It might a good start in your research about school selectivity. Princeton Review also has an article on their website and it lists good info on college ratings. A similar topic, College Rankings has been elaborated in detail at University of Illinois at Urbana's website.