Ah let me clarify (and this is something that frankly all of the Harris students were confused about as well and aren't sure if this is a new trend or an off year. I think it's the new trend):

Up until 2016, Harris's PhD program had a class size of about 10-15. The 1st-year PhD Core (taught by top economists/comparable to a top 30 Econ PhD) was almost exclusively taken by these 10-15 kids (might be 1 or two kids from other departments or an MPP).

Then in 2016 they started the new "MACRM" program, which was exclusively offered to students who had applied to the PhD program and were close but didn't get in. The program was meant to be a way for these students to prove themselves and if they did well in the first year courses, the goal would be to directly continue as a PhD student. They had 2 such students, and one of them was admitted as a PhD student the next year.

The following year, they had a class size of 9 PhD students, and accepted 3 into the 'MACRM' (aka unfunded first year PhD), and also only 1 was allowed to continue as a PhD student during their second year (funded from that point on), and the other two kids were stuck applying elsewhere.

Now this year, they have changed things radically. Instead of the MACRM being only a few marginal students who might all have the chance to continue if they do well, the MACRM has 20 students (at most, some students have a 25% tuition waiver -- which still means $65k in loans for the first year of tuition/living expenses). I actually just re-counted, and there are only 4 PhD students in this year's cohort.

So out of the 20 MACRM and 4 PhD students, it is unclear how many of the MACRM students will be allowed to continue on as PhD students next year. In fact, some of the MACRM students are outperforming all 4 PhD admits in the core courses, so it's unclear what will happen. It seems like they will still only accept a few of them to continue (maybe even just 1-2), and then the rest will all be applying to other PhD programs. The consensus among the 20 MACRM admits is that they were all under the impression that there were only going to be 2-3 students in that program and that they would have a reasonable chance (rather than 1 in 20) of continuing as a PhD student. (you can search Chris Blattman's blog post about the MACRM where he stated only 2-3 students are expected to be in the program).

So not sure if they just had an off year as far as many PhD admits not accepting the offer, and a high # of students unexpectedly accepting the MACRM offer, or if they are planning to gradually cut their PhD size in order to save on 1st year funding...