Pretty much.

For instance focusing on PR size. PR size may be a side effect of the maturity of the product, the type of work being performed, the complexity or lack thereof of the real world space their problems touch, and in the methodologies habits and practices of the team.

Just looking at PR size or really any other single dimensional KPI lead you to lose the nuance that was driving the productivity in the first place.

Honestly in my experience high productivity comes from a high level of unity in how the team thinks, approaches problems, and how diligent they are about their decisions. And isn’t necessarily something that’s strictly learned, it can be about getting the right people together.