A couple of recent articles on the situation of scitech doctoral studies in the US and Canada. For the Canadian situation, see the following CTV story which references this StatsCan report (and here for the report itself). For the US, the article Lost Dominance in Ph.D. Production by Scott Jaschik is mostly about the growth of programs outside the US compared to within. There is much lively debate in the comments section. The original report from the National Bureau of Economic Research is avaible here.