Probabilistic Information Retrieval Probability Ranking Principle The probability ranking principle If a reference retrieval system s response to each request is a ranking of the documents in the collection in order of decreasing probability of relevance to the user who submitted the request, where the probabilities are estimated as accurately as possible on the basis of whatever data have been made available to the system for this purpose, the overall effectiveness of the system to its user will be the best that is obtainable on the basis of those data [1960s/1970s]S Robertson, W.S. Cooper, M.E. Maron van Rijsbergen (1979: 113 ); Manning Schutze(1999: 538)Probabilistic Information Retrieval 8 The Probability Ranking Principle “If a reference retrieval system's response to each request is a ranking of the documents in the collection in order of decreasing probability of relevance to the user who submitted the request, where the probabilities are estimated as accurately as possible on the basis of whatever data have been made available to the system for this purpose, the overall effectiveness of the system to its user will be the best that is obtainable on the basis of those data.” ▪ [1960s/1970s] S. Robertson, W.S. Cooper, M.E. Maron; van Rijsbergen (1979:113); Manning & Schütze (1999:538) Probability Ranking Principle