The Longer report on Proposal Pressures that was not in finished form by the March 2015 AAAC report, may be a good place to start. What are the questions not yet answered, what additional information is required to make a case.
Further analysis of the proposal per year and proposal per 3 year NSF data
A few more snapshots of the NASA Astrophysics merit criteria.
Explore further effect of pre-proposal strategy on those that have tried it
Detailed comparison of DOE Cosmic Frontier model vs NSF, NASA wrt results. Any lessons to be learned?
Better data on cost per proposal and number of PI's on proposals, etc
Investigate the trend on the average funding per proposal in both agencies
Bring the Heliophysics and Planetary stats up to the level of NASA/APD and NSF/AST