Ratings are usually all heuristics. they are suhbjective issues and sometimes even fudged, as an institute trying to gain prominance pushes its way in these cards using back entry. Had it been for me, i'll never rate IITD lowest among the IITs anyways (D being my alma mater)

. But all the same, when it comes to knowing the good schools around the country, these listings, do give you a good idea in terms of names. Everything else is opiniunated. Thats exactly why we have the forums in place, where we can all shout and say what we think is right, thus generating a rough, but rather correct picture. so
nunoxic's point is completely correct when he says the ratings are not right. but we should not discard these ratings and should use the list as a cumulative listing of all colleges does give you a good starting point for personal research.
cheers
~admin