Here's a new working paper on STEM majors.

STEM Careers and Technological Change
by David J. Deming, Kadeem L. Noray - #25065 (ED EFG LS PR)
Abstract:
Science, Technology, Engineering, and Math (STEM) jobs are a key
contributor to economic growth and national competitiveness. Yet
STEM workers are perceived to be in short supply. This paper
shows that the "STEM shortage" phenomenon is explained by
technological change, which introduces new job tasks and makes
old ones obsolete. We find that the initially high economic
return to applied STEM degrees declines by more than 50 percent
in the first decade of working life. This coincides with a rapid
exit of college graduates from STEM occupations. Using detailed
job vacancy data, we show that STEM jobs changed especially
quickly over the last decade, leading to flatter age-earnings
profiles as the skills of older cohorts became obsolete. Our
findings highlight the importance of technology-specific skills
in explaining life-cycle returns to education, and show that STEM
jobs are the leading edge of technology diffusion in the labor
market.