I somewhat disagree with this.
As per 2014 charting outcomes:
http://www.nrmp.org/wp-content/uploads/2014/09/Charting-Outcomes-2014-Final.pdf
EM Average Scores: Step 1: 230, Step 2: 243
IM Average Scores: Step 1: 231, Step 2: 243
So exactly the same with scores (Among U.S MD). But yes, higher AOA/publication/PhD. But ER has never been a specialty geared towards research.
And based on anecdotal data, I suspect ER will be much higher for 2016 with regards to USMLE scores than IM, but thats just my hunch.
and no slight to IMGs, but much higher percentage of IMGs in IM vs. ER:
http://www.nrmp.org/wp-content/uploads/2015/05/Main-Match-Results-and-Data-2015_final.pdf
Table 8:
ER - 79% (US MD)
IM - 49% (US MD)
Psych - 57% (US MD)
So generally a specialty's competitiveness is based on %IMG.
With regards to Psych vs. IM, well scores are higher in IM in 2014, but not that much higher:
Psych: Step 1 (220), Step 2 (233)
IM : Step 1 (231), Step 2 (243)
And again, I think this gap will have shrunk in 2016, but just my prediction.
Psych also had more PhD in 2014 (4.5 vs. 4.1) and same number of publications (3.9 vs. 3.8).
So really IM only takes the cake with USMLE Scores, and as we know, a lot of IMGs have inflated scores by taking off 1-2 years to prep for the boards.
And as mentioned above, higher percentage of IMG in IM vs. Psych. Over 180 applicants increase in applications for psych (for 1400 spots), whereas IM actually had a slight decrease in applicants (5687 to 5621, compared to previous years where IM increased by 300-400 applicants from the previous years). Its actually the first time in over 15 years Categorical IM has seen a DECREASE in applicants.
https://www.aamc.org/services/eras/stats/
So I predict psych will be overtaking IM in competitiveness over the next couple years (if this trend continues) with psych leveling out on USMLE scores as well.