First step was the Data Science exam, which was a multiple choice math exam. Questions about stat, algorithms, linear algebra, calculus, .... it was overall an easy exam but the timing was limited. I passed that exam. Then I had three technical & behavioral interviews. Very nice and friendly people, and different levels of questions from easy to hard. Then I was waiting for a while until I received the news that I am selected, and then few month later the offer came! However, the offer was very underwhelming (between $125-135K for a senior data scientist in Maryland!!). Specially, I have more than a decade of research experience and graduated from one of the top Universities in the US! I've always wanted to work for NSA due to interesting projects they have, but I should have got a pay cut of more than 20K to work there!! Overall, the long process and wasted efforts didn't worth the offer I received, and I believe good data scientist should be able to get much better offers elsewhere! Seems NSA hasn't adjusted it's income levels for inflation and of course the high demand for data scientists! Unless you don't care about money at all, I don't recommend applying because it's a very long and fruitless process!