I get the feeling the PPP does not really reflect reality as intended
One hand it gives schools from 3rd countries a chance to compete, but in reality, most people ask for advice to choose schools in U.S. the U.K. the EU and lately Canada - and real salaries (not PPP ones) are definitely a factor
It's a bit tricky for schools in countries like India where the overall salaries in real terms are far lower than other regions represented in the rankings. I think the real average salary of recent IIMA grads converts to around $27,000 USD - if you're comparing real values then there's no way that school could compete against MBAs in the US / UK / Europe / most rest of the west. Same thing with a school like Fudan, where the converted average salaries in real terms are around $38,000 USD.
However, if you look at other factors like cost of living for MBAs living in a country like India versus the rest of the west, the whole picture looks a bit different. That $27k is going to go a long way, in perspective.
Even so, I agree that it's often like comparing apples to oranges. I think the FT - at least for this Global MBA Ranking - does a good job in weighing all the various factors that go into the ranking, relatively fairly. It's never going to be perfect, but it's sort of 'good enough' without having to have separate rankings for each country.
The EMBA ranking is another story. I think in this case PPP works to inflate the salaries of partner EMBA where one b-school partner is in a country like China.