It is really depend on the focus or concentration of your PhD studies. If you plan to go back to Latin America, I would suggest Yale IDE program. They are quantitative oriented, so you would not be behind in building your math background. Secondly, it would be a great path if you want to pursue a development career (public policy, economic adviser, etc...). While a MA at NYU may put you on track for a PhD, it's only a one year program. So technically, you only have, at max, 1 semester to impress on potential PhD committee. IDE, on the other hand, would put you in a better position if you are considering Yale Econ PhD a potential program. All depend on where you want to pursue your PhD. NYU or Yale? Personally, I would prefer Yale.