The results were expressed in grade equivalents, which allowed one to see that rather than progressing, both groups had fallen further behind in terms of grade level.
This passage is similarly hard to understand:
Moreover, the more coaching a teacher received, the more growth the students had, on average. The difference between students whose teachers had more coaching and those who did not was statistically significant.
Again, no data is provided to back up either claim, and no definition of “more coaching” is offered in which would allow one to evaluate the claim made by the second statement. How much more coaching was needed for a teacher to see a statistically significant gain in his or her students?
No information is provided either as to whether the coaches believed their training was useful, even though a third of school leaders reported that "the coach was out of the building too often for professional learning."
All in all, there needs to be a more comprehensive study with much more data provided before one can be assured that the program is providing benefits to kids that are worth the cost. And this analysis would be far more credible coming from an experienced and independent research outfit like RAND.