Implications of alternative choices of OMs for development tuning targets

Questions have been raised about how the choice of OM (or group of OMs) for development tuning impacts the distribution of results across the full set of 96 OMs of the interim grid. The results for three different choices are examined for the FXP CMP for 100 tuning (Br30 = 1 for both Eastern and Western stocks for deterministic projections). Although the Br30 distributions for the whole interim grid shift up or down to different extents, relative to each of their medians, these distributions are unchanged for all practical purposes. This argues for using a single OM as the basis for development tuning, in the interests of simplicity of implementation.