On comparing CMPS across different development tunings and the associated pertinence of OM weighting

Medians and lower %iles for the East and West Br30 and AvC30 performance statistics over the interim grid of OMs are compared for the most recent versions of the Butterworth-Rademeyer (BR) and Carruthers (TC) CMPs. Each CMP has been tuned to the agreed development tuning targets of median values for Br30 West (1.00, 1.25, 1.50), and all to the same value of Br30 East. Performances are very similar, despite rather different CMP structures. The differences are generally independent of the development tuning value for the western stock. This suggests that CMP performance comparisons can proceed before awaiting agreement on OM weightings; these are primarily of consequence for finalization tuning (which will be needed in 2022 when the Commission is to make its final MP choice). The performances of different CMPs will need to be compared over a much wider set of performances statistics than considered in the illustrative example presented. This large task will require the allocation of considerable time for discussion in meetings of the BFT WG during 2021 for the MP development process to remain on schedule.