The attached sets up an experiment: create a vector of 50 "probabilities" at random, uniformly distributed in (0.0, 1.0) combine them using Paul Graham's scheme, and using Gary Robinson's scheme record the results repeat 5000 times The results should look familiar for those playing this game from the start: Result for random vectors of 50 probs, + 0 forced to 0.99 Graham combining 5000 items; mean 0.50; sdev 0.47 -> <stat> min 9.54792e-022; median 0.506715; max 1 * = 35 items 0.00 2051 *********************************************************** 0.05 100 *** 0.10 75 *** 0.15 63 ** 0.20 44 ** 0.25 35 * 0.30 40 ** 0.35 34 * 0.40 30 * 0.45 25 * 0.50 34 * 0.55 32 * 0.60 31 * 0.65 24 * 0.70 39 ** 0.75 43 ** 0.80 56 ** 0.85 55 ** 0.90 108 **** 0.95 2081 ************************************************************ Robinson combining 5000 items; mean 0.50; sdev 0.04 -> <stat> min 0.350831; median 0.500083; max 0.649056 * = 34 items 0.00 0 0.05 0 0.10 0 0.15 0 0.20 0 0.25 0 0.30 0 0.35 20 * 0.40 450 ************** 0.45 2027 ************************************************************ 0.50 2019 ************************************************************ 0.55 452 ************** 0.60 32 * 0.65 0 0.70 0 0.75 0 0.80 0 0.85 0 0.90 0 0.95 0 IOW, Paul's scheme is almost always "certain" given 50 discriminators, even in the face of random input. Gary's is never "certain" then. OTOH, do the experiment all over again, but attach one prob of 0.99 to each random vector of 50 probs. The probs are now systematically biased: Result for random vectors of 50 probs, + 1 forced to 0.99 Graham combining 5000 items; mean 0.65; sdev 0.45 -> <stat> min 8.36115e-021; median 0.992403; max 1 * = 47 items 0.00 1353 ***************************** 0.05 92 ** 0.10 50 ** 0.15 42 * 0.20 40 * 0.25 35 * 0.30 26 * 0.35 31 * 0.40 32 * 0.45 31 * 0.50 23 * 0.55 29 * 0.60 30 * 0.65 31 * 0.70 45 * 0.75 33 * 0.80 58 ** 0.85 84 ** 0.90 113 *** 0.95 2822 ************************************************************* Robinson combining 5000 items; mean 0.51; sdev 0.04 -> <stat> min 0.377845; median 0.513446; max 0.637992 * = 42 items 0.00 0 0.05 0 0.10 0 0.15 0 0.20 0 0.25 0 0.30 0 0.35 2 * 0.40 181 ***** 0.45 1549 ************************************* 0.50 2527 ************************************************************* 0.55 698 ***************** 0.60 43 ** 0.65 0 0.70 0 0.75 0 0.80 0 0.85 0 0.90 0 0.95 0 There's a dramatic difference in the Paul results, while the Gary results move sublty (in comparison). If we force 10 additional .99 spamprobs, the differences are night and day: Result for random vectors of 50 probs, + 10 forced to 0.99 Graham combining 5000 items; mean 1.00; sdev 0.01 -> <stat> min 0.213529; median 1; max 1 * = 82 items 0.00 0 0.05 0 0.10 0 0.15 0 0.20 1 * 0.25 0 0.30 1 * 0.35 0 0.40 0 0.45 0 0.50 0 0.55 0 0.60 0 0.65 0 0.70 0 0.75 0 0.80 0 0.85 0 0.90 0 0.95 4998 ************************************************************* Robinson combining 5000 items; mean 0.59; sdev 0.03 -> <stat> min 0.49794; median 0.58555; max 0.694905 * = 51 items 0.00 0 0.05 0 0.10 0 0.15 0 0.20 0 0.25 0 0.30 0 0.35 0 0.40 0 0.45 2 * 0.50 412 ********* 0.55 3068 ************************************************************* 0.60 1447 ***************************** 0.65 71 ** 0.70 0 0.75 0 0.80 0 0.85 0 0.90 0 0.95 0 It's hard to know what to make of this, especially in light of the claim that Gary-combining has been proven to be the most sensitive possible test for rejecting the hypothesis that a collection of probs is uniformly distributed. At least in this test, Paul-combining seemed far more sensitive (even when the data is random <wink>). Intuitively, it *seems* like it would be good to get something not so insanely sensitive to random input as Paul-combining, but more sensitive to overwhelming amounts of evidence than Gary-combining. Even forcing 50 spamprobs of 0.99, the latter only moves up to an average of 0.7: Result for random vectors of 50 probs, + 50 forced to 0.99 Graham combining 5000 items; mean 1.00; sdev 0.00 -> <stat> min 1; median 1; max 1 * = 82 items 0.00 0 0.05 0 0.10 0 0.15 0 0.20 0 0.25 0 0.30 0 0.35 0 0.40 0 0.45 0 0.50 0 0.55 0 0.60 0 0.65 0 0.70 0 0.75 0 0.80 0 0.85 0 0.90 0 0.95 5000 ************************************************************* Robinson combining 5000 items; mean 0.70; sdev 0.02 -> <stat> min 0.628976; median 0.704543; max 0.810235 * = 45 items 0.00 0 0.05 0 0.10 0 0.15 0 0.20 0 0.25 0 0.30 0 0.35 0 0.40 0 0.45 0 0.50 0 0.55 0 0.60 40 * 0.65 2070 ********************************************** 0.70 2743 ************************************************************* 0.75 146 **** 0.80 1 * 0.85 0 0.90 0 0.95 0