BM25 is a probabilistic weighting scheme used by Xapian that combines previous models (BM11 and BM15) with a scaling factor to improve term weighting in information retrieval. Recent TREC tests have shown it to be the best known probabilistic weighting scheme, with default parameters of k1=1, k2=0, k3=1, and b=0.5 that can be tuned for specific collections and query types.
An interactive visualization of 562,816 survey respondents' sexual interests from the Big Kink Survey, weighted to match population demographics. The map plots nearly 600 kinks by prevalence, taboo level, and demographic preferences, with detailed methodology for handling sparse data and statistical adjustments.