Considerations about the rankings of High Schools

The publication of rankings about high schools, started in 2001, had a significant impact at several levels, initiating a series of comments and speculations in mainstream media and influencing the decisions (or at least the aspirations) of many people. Taking advantage of the availability of five years of data, and the possibility of comparing the rankings, our data analysis has tried to verify a posteriori if the implicit hypothesis in the enthusiastic adoption of rankings is reasonable. Using other words, are the rankings an accurate measure of the quality, or of the effectiveness, of schools? The main conclusion points to the necessity of not overrating the rankings based on examinations, nevertheless considering them as a useful piece of information, for school's self-assessment and for comparing comparable things. On the other side, being evident the social interest for these kind of orderings, it is worth investing on the identification of quality characterization factors that could be used to complement the information, always preferring understandable, objective and accessible aspects.