World Reputation Rankings 2016: how the top 30 places have changed

I sometimes wonder how much of the changes we see are due to material changes to the raw survey result, and how much is due change in sampling methodology and weights given in each category. I'm not saying this isn't useful but if TMES wants to confidently make broad and sweeping statement regarding the "raise" of Asian schools or consistent raise of Columbia, for example, having different sample and evaluation methodology every year really doesn't give me confidence to the validity of such proclamation. Reputation is hard earned over decades, even centuries. Drastic changes year over year should be a rare occurrence...