Document (#33070)

Author

Bar-Ilan, J.

Title

Comparing rankings of search results on the Web

Source

Information processing and management. 41(2005) no.6, S.1511-1519

Year

2005

Abstract

The Web has become an information source for professional data gathering. Because of the vast amounts of information on almost all topics, one cannot systematically go over the whole set of results, and therefore must rely on the ordering of the results by the search engine. It is well known that search engines on the Web have low overlap in terms of coverage. In this study we measure how similar are the rankings of search engines on the overlapping results. We compare rankings of results for identical queries retrieved from several search engines. The method is based only on the set of URLs that appear in the answer sets of the engines being compared. For comparing the similarity of rankings of two search engines, the Spearman correlation coefficient is computed. When comparing more than two sets Kendall's W is used. These are well-known measures and the statistical significance of the results can be computed. The methods are demonstrated on a set of 15 queries that were submitted to four large Web search engines. The findings indicate that the large public search engines on the Web employ considerably different ranking algorithms.

Footnote

Beitrag in einem "Special Issue on Infometrics"

Theme

Suchmaschinen

Similar documents (author)

1. Ilan, J. Bar- => Bar-Ilan, J.: 4.27

   4.270203 = sum of:
     4.270203 = weight(author_txt:ilan in 5393) [ClassicSimilarity], result of:
       4.270203 = fieldWeight in 5393, product of:
         1.4142135 = tf(freq=2.0), with freq of:
           2.0 = termFreq=2.0
         8.051972 = idf(docFreq=36, maxDocs=42740)
         0.375 = fieldNorm(doc=5393)
   

2. Ilan, E. Bar- => Bar-Ilan, E.: 4.27

   4.270203 = sum of:
     4.270203 = weight(author_txt:ilan in 5394) [ClassicSimilarity], result of:
       4.270203 = fieldWeight in 5394, product of:
         1.4142135 = tf(freq=2.0), with freq of:
           2.0 = termFreq=2.0
         8.051972 = idf(docFreq=36, maxDocs=42740)
         0.375 = fieldNorm(doc=5394)
   

3. Bar-Ilan, J.: Information hub blogs (2005) 4.03

   4.025986 = sum of:
     4.025986 = weight(author_txt:ilan in 193) [ClassicSimilarity], result of:
       4.025986 = fieldWeight in 193, product of:
         1.0 = tf(freq=1.0), with freq of:
           1.0 = termFreq=1.0
         8.051972 = idf(docFreq=36, maxDocs=42740)
         0.5 = fieldNorm(doc=193)
   

4. Bar-Ilan, J.: Evaluating the stability of the search tools Hotbot and Snap : a case study (2000) 4.03

   4.025986 = sum of:
     4.025986 = weight(author_txt:ilan in 2181) [ClassicSimilarity], result of:
       4.025986 = fieldWeight in 2181, product of:
         1.0 = tf(freq=1.0), with freq of:
           1.0 = termFreq=1.0
         8.051972 = idf(docFreq=36, maxDocs=42740)
         0.5 = fieldNorm(doc=2181)
   

5. Bar-Ilan, J.: On the overlap, the precision and estimated recall of search engines : a case study of the query 'Erdös' (1998) 4.03

   4.025986 = sum of:
     4.025986 = weight(author_txt:ilan in 4754) [ClassicSimilarity], result of:
       4.025986 = fieldWeight in 4754, product of:
         1.0 = tf(freq=1.0), with freq of:
           1.0 = termFreq=1.0
         8.051972 = idf(docFreq=36, maxDocs=42740)
         0.5 = fieldNorm(doc=4754)
   

Similar documents (content)

1. Bar-Ilan, J.; Levene, M.; Mat-Hassan, M.: Methods for evaluating dynamic changes in search engine rankings : a case study (2006) 0.60

   0.59711486 = sum of:
     0.59711486 = product of:
       1.4927871 = sum of:
         0.063216686 = weight(abstract_txt:overlap in 1742) [ClassicSimilarity], result of:
           0.063216686 = score(doc=1742,freq=2.0), product of:
             0.11770487 = queryWeight, product of:
               1.003821 = boost
               6.9443917 = idf(docFreq=111, maxDocs=42740)
               0.016885111 = queryNorm
             0.5370779 = fieldWeight in 1742, product of:
               1.4142135 = tf(freq=2.0), with freq of:
                 2.0 = termFreq=2.0
               6.9443917 = idf(docFreq=111, maxDocs=42740)
               0.0546875 = fieldNorm(doc=1742)
         0.054093655 = weight(abstract_txt:identical in 1742) [ClassicSimilarity], result of:
           0.054093655 = score(doc=1742,freq=1.0), product of:
             0.13366391 = queryWeight, product of:
               1.0697103 = boost
               7.400211 = idf(docFreq=70, maxDocs=42740)
               0.016885111 = queryNorm
             0.40469903 = fieldWeight in 1742, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               7.400211 = idf(docFreq=70, maxDocs=42740)
               0.0546875 = fieldNorm(doc=1742)
         0.01269888 = weight(abstract_txt:that in 1742) [ClassicSimilarity], result of:
           0.01269888 = score(doc=1742,freq=3.0), product of:
             0.05598519 = queryWeight, product of:
               1.3846042 = boost
               2.3946586 = idf(docFreq=10595, maxDocs=42740)
               0.016885111 = queryNorm
             0.22682571 = fieldWeight in 1742, product of:
               1.7320508 = tf(freq=3.0), with freq of:
                 3.0 = termFreq=3.0
               2.3946586 = idf(docFreq=10595, maxDocs=42740)
               0.0546875 = fieldNorm(doc=1742)
         0.049763426 = weight(abstract_txt:queries in 1742) [ClassicSimilarity], result of:
           0.049763426 = score(doc=1742,freq=2.0), product of:
             0.12643194 = queryWeight, product of:
               1.4713042 = boost
               5.0892105 = idf(docFreq=715, maxDocs=42740)
               0.016885111 = queryNorm
             0.39359853 = fieldWeight in 1742, product of:
               1.4142135 = tf(freq=2.0), with freq of:
                 2.0 = termFreq=2.0
               5.0892105 = idf(docFreq=715, maxDocs=42740)
               0.0546875 = fieldNorm(doc=1742)
         0.11810859 = weight(abstract_txt:computed in 1742) [ClassicSimilarity], result of:
           0.11810859 = score(doc=1742,freq=1.0), product of:
             0.28343117 = queryWeight, product of:
               2.2029157 = boost
               7.619839 = idf(docFreq=56, maxDocs=42740)
               0.016885111 = queryNorm
             0.41670996 = fieldWeight in 1742, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               7.619839 = idf(docFreq=56, maxDocs=42740)
               0.0546875 = fieldNorm(doc=1742)
         0.09047836 = weight(abstract_txt:comparing in 1742) [ClassicSimilarity], result of:
           0.09047836 = score(doc=1742,freq=1.0), product of:
             0.2716357 = queryWeight, product of:
               2.641272 = boost
               6.0907364 = idf(docFreq=262, maxDocs=42740)
               0.016885111 = queryNorm
             0.33308715 = fieldWeight in 1742, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               6.0907364 = idf(docFreq=262, maxDocs=42740)
               0.0546875 = fieldNorm(doc=1742)
         0.09141369 = weight(abstract_txt:results in 1742) [ClassicSimilarity], result of:
           0.09141369 = score(doc=1742,freq=7.0), product of:
             0.18013932 = queryWeight, product of:
               3.0418582 = boost
               3.5072412 = idf(docFreq=3482, maxDocs=42740)
               0.016885111 = queryNorm
             0.5074611 = fieldWeight in 1742, product of:
               2.6457512 = tf(freq=7.0), with freq of:
                 7.0 = termFreq=7.0
               3.5072412 = idf(docFreq=3482, maxDocs=42740)
               0.0546875 = fieldNorm(doc=1742)
         0.489034 = weight(abstract_txt:rankings in 1742) [ClassicSimilarity], result of:
           0.489034 = score(doc=1742,freq=8.0), product of:
             0.4603972 = queryWeight, product of:
               3.9705935 = boost
               6.8671 = idf(docFreq=120, maxDocs=42740)
               0.016885111 = queryNorm
             1.0622002 = fieldWeight in 1742, product of:
               2.828427 = tf(freq=8.0), with freq of:
                 8.0 = termFreq=8.0
               6.8671 = idf(docFreq=120, maxDocs=42740)
               0.0546875 = fieldNorm(doc=1742)
         0.1559739 = weight(abstract_txt:search in 1742) [ClassicSimilarity], result of:
           0.1559739 = score(doc=1742,freq=9.0), product of:
             0.26035568 = queryWeight, product of:
               4.2226744 = boost
               3.6515355 = idf(docFreq=3014, maxDocs=42740)
               0.016885111 = queryNorm
             0.5990801 = fieldWeight in 1742, product of:
               3.0 = tf(freq=9.0), with freq of:
                 9.0 = termFreq=9.0
               3.6515355 = idf(docFreq=3014, maxDocs=42740)
               0.0546875 = fieldNorm(doc=1742)
         0.368006 = weight(abstract_txt:engines in 1742) [ClassicSimilarity], result of:
           0.368006 = score(doc=1742,freq=7.0), product of:
             0.4799027 = queryWeight, product of:
               5.362715 = boost
               5.2998624 = idf(docFreq=579, maxDocs=42740)
               0.016885111 = queryNorm
             0.76683456 = fieldWeight in 1742, product of:
               2.6457512 = tf(freq=7.0), with freq of:
                 7.0 = termFreq=7.0
               5.2998624 = idf(docFreq=579, maxDocs=42740)
               0.0546875 = fieldNorm(doc=1742)
       0.4 = coord(10/25)
   

2. Bar-Ilan, J.; Keenoy, K.; Yaari, E.; Levene, M.: User rankings of search engine results (2007) 0.54

   0.5393366 = sum of:
     0.5393366 = product of:
       1.3483415 = sum of:
         0.08120369 = weight(abstract_txt:urls in 2471) [ClassicSimilarity], result of:
           0.08120369 = score(doc=2471,freq=2.0), product of:
             0.12724161 = queryWeight, product of:
               1.0436951 = boost
               7.220239 = idf(docFreq=84, maxDocs=42740)
               0.016885111 = queryNorm
             0.638185 = fieldWeight in 2471, product of:
               1.4142135 = tf(freq=2.0), with freq of:
                 2.0 = termFreq=2.0
               7.220239 = idf(docFreq=84, maxDocs=42740)
               0.0625 = fieldNorm(doc=2471)
         0.06182132 = weight(abstract_txt:identical in 2471) [ClassicSimilarity], result of:
           0.06182132 = score(doc=2471,freq=1.0), product of:
             0.13366391 = queryWeight, product of:
               1.0697103 = boost
               7.400211 = idf(docFreq=70, maxDocs=42740)
               0.016885111 = queryNorm
             0.46251318 = fieldWeight in 2471, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               7.400211 = idf(docFreq=70, maxDocs=42740)
               0.0625 = fieldNorm(doc=2471)
         0.027221238 = weight(abstract_txt:large in 2471) [ClassicSimilarity], result of:
           0.027221238 = score(doc=2471,freq=1.0), product of:
             0.09746991 = queryWeight, product of:
               1.2918419 = boost
               4.468454 = idf(docFreq=1331, maxDocs=42740)
               0.016885111 = queryNorm
             0.27927837 = fieldWeight in 2471, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               4.468454 = idf(docFreq=1331, maxDocs=42740)
               0.0625 = fieldNorm(doc=2471)
         0.016758177 = weight(abstract_txt:that in 2471) [ClassicSimilarity], result of:
           0.016758177 = score(doc=2471,freq=4.0), product of:
             0.05598519 = queryWeight, product of:
               1.3846042 = boost
               2.3946586 = idf(docFreq=10595, maxDocs=42740)
               0.016885111 = queryNorm
             0.29933232 = fieldWeight in 2471, product of:
               2.0 = tf(freq=4.0), with freq of:
                 4.0 = termFreq=4.0
               2.3946586 = idf(docFreq=10595, maxDocs=42740)
               0.0625 = fieldNorm(doc=2471)
         0.056872487 = weight(abstract_txt:queries in 2471) [ClassicSimilarity], result of:
           0.056872487 = score(doc=2471,freq=2.0), product of:
             0.12643194 = queryWeight, product of:
               1.4713042 = boost
               5.0892105 = idf(docFreq=715, maxDocs=42740)
               0.016885111 = queryNorm
             0.4498269 = fieldWeight in 2471, product of:
               1.4142135 = tf(freq=2.0), with freq of:
                 2.0 = termFreq=2.0
               5.0892105 = idf(docFreq=715, maxDocs=42740)
               0.0625 = fieldNorm(doc=2471)
         0.13498124 = weight(abstract_txt:computed in 2471) [ClassicSimilarity], result of:
           0.13498124 = score(doc=2471,freq=1.0), product of:
             0.28343117 = queryWeight, product of:
               2.2029157 = boost
               7.619839 = idf(docFreq=56, maxDocs=42740)
               0.016885111 = queryNorm
             0.47623995 = fieldWeight in 2471, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               7.619839 = idf(docFreq=56, maxDocs=42740)
               0.0625 = fieldNorm(doc=2471)
         0.08829562 = weight(abstract_txt:results in 2471) [ClassicSimilarity], result of:
           0.08829562 = score(doc=2471,freq=5.0), product of:
             0.18013932 = queryWeight, product of:
               3.0418582 = boost
               3.5072412 = idf(docFreq=3482, maxDocs=42740)
               0.016885111 = queryNorm
             0.49015188 = fieldWeight in 2471, product of:
               2.236068 = tf(freq=5.0), with freq of:
                 5.0 = termFreq=5.0
               3.5072412 = idf(docFreq=3482, maxDocs=42740)
               0.0625 = fieldNorm(doc=2471)
         0.3951992 = weight(abstract_txt:rankings in 2471) [ClassicSimilarity], result of:
           0.3951992 = score(doc=2471,freq=4.0), product of:
             0.4603972 = queryWeight, product of:
               3.9705935 = boost
               6.8671 = idf(docFreq=120, maxDocs=42740)
               0.016885111 = queryNorm
             0.8583875 = fieldWeight in 2471, product of:
               2.0 = tf(freq=4.0), with freq of:
                 4.0 = termFreq=4.0
               6.8671 = idf(docFreq=120, maxDocs=42740)
               0.0625 = fieldNorm(doc=2471)
         0.16806126 = weight(abstract_txt:search in 2471) [ClassicSimilarity], result of:
           0.16806126 = score(doc=2471,freq=8.0), product of:
             0.26035568 = queryWeight, product of:
               4.2226744 = boost
               3.6515355 = idf(docFreq=3014, maxDocs=42740)
               0.016885111 = queryNorm
             0.6455064 = fieldWeight in 2471, product of:
               2.828427 = tf(freq=8.0), with freq of:
                 8.0 = termFreq=8.0
               3.6515355 = idf(docFreq=3014, maxDocs=42740)
               0.0625 = fieldNorm(doc=2471)
         0.3179273 = weight(abstract_txt:engines in 2471) [ClassicSimilarity], result of:
           0.3179273 = score(doc=2471,freq=4.0), product of:
             0.4799027 = queryWeight, product of:
               5.362715 = boost
               5.2998624 = idf(docFreq=579, maxDocs=42740)
               0.016885111 = queryNorm
             0.6624828 = fieldWeight in 2471, product of:
               2.0 = tf(freq=4.0), with freq of:
                 4.0 = termFreq=4.0
               5.2998624 = idf(docFreq=579, maxDocs=42740)
               0.0625 = fieldNorm(doc=2471)
       0.4 = coord(10/25)
   

3. Spink, A.; Jansen, B.J.; Blakely, C.; Koshman, S.: ¬A study of results overlap and uniqueness among major Web search engines (2006) 0.42

   0.4172637 = sum of:
     0.4172637 = product of:
       1.1590657 = sum of:
         0.089401886 = weight(abstract_txt:overlap in 2994) [ClassicSimilarity], result of:
           0.089401886 = score(doc=2994,freq=4.0), product of:
             0.11770487 = queryWeight, product of:
               1.003821 = boost
               6.9443917 = idf(docFreq=111, maxDocs=42740)
               0.016885111 = queryNorm
             0.7595428 = fieldWeight in 2994, product of:
               2.0 = tf(freq=4.0), with freq of:
                 4.0 = termFreq=4.0
               6.9443917 = idf(docFreq=111, maxDocs=42740)
               0.0546875 = fieldNorm(doc=2994)
         0.04595886 = weight(abstract_txt:submitted in 2994) [ClassicSimilarity], result of:
           0.04595886 = score(doc=2994,freq=1.0), product of:
             0.119902834 = queryWeight, product of:
               1.0131501 = boost
               7.00893 = idf(docFreq=104, maxDocs=42740)
               0.016885111 = queryNorm
             0.38330087 = fieldWeight in 2994, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               7.00893 = idf(docFreq=104, maxDocs=42740)
               0.0546875 = fieldNorm(doc=2994)
         0.041254997 = weight(abstract_txt:large in 2994) [ClassicSimilarity], result of:
           0.041254997 = score(doc=2994,freq=3.0), product of:
             0.09746991 = queryWeight, product of:
               1.2918419 = boost
               4.468454 = idf(docFreq=1331, maxDocs=42740)
               0.016885111 = queryNorm
             0.42325878 = fieldWeight in 2994, product of:
               1.7320508 = tf(freq=3.0), with freq of:
                 3.0 = termFreq=3.0
               4.468454 = idf(docFreq=1331, maxDocs=42740)
               0.0546875 = fieldNorm(doc=2994)
         0.007331702 = weight(abstract_txt:that in 2994) [ClassicSimilarity], result of:
           0.007331702 = score(doc=2994,freq=1.0), product of:
             0.05598519 = queryWeight, product of:
               1.3846042 = boost
               2.3946586 = idf(docFreq=10595, maxDocs=42740)
               0.016885111 = queryNorm
             0.13095789 = fieldWeight in 2994, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               2.3946586 = idf(docFreq=10595, maxDocs=42740)
               0.0546875 = fieldNorm(doc=2994)
         0.09952685 = weight(abstract_txt:queries in 2994) [ClassicSimilarity], result of:
           0.09952685 = score(doc=2994,freq=8.0), product of:
             0.12643194 = queryWeight, product of:
               1.4713042 = boost
               5.0892105 = idf(docFreq=715, maxDocs=42740)
               0.016885111 = queryNorm
             0.78719705 = fieldWeight in 2994, product of:
               2.828427 = tf(freq=8.0), with freq of:
                 8.0 = termFreq=8.0
               5.0892105 = idf(docFreq=715, maxDocs=42740)
               0.0546875 = fieldNorm(doc=2994)
         0.03713331 = weight(abstract_txt:sets in 2994) [ClassicSimilarity], result of:
           0.03713331 = score(doc=2994,freq=1.0), product of:
             0.1310496 = queryWeight, product of:
               1.4979314 = boost
               5.1813135 = idf(docFreq=652, maxDocs=42740)
               0.016885111 = queryNorm
             0.2833531 = fieldWeight in 2994, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               5.1813135 = idf(docFreq=652, maxDocs=42740)
               0.0546875 = fieldNorm(doc=2994)
         0.103653386 = weight(abstract_txt:results in 2994) [ClassicSimilarity], result of:
           0.103653386 = score(doc=2994,freq=9.0), product of:
             0.18013932 = queryWeight, product of:
               3.0418582 = boost
               3.5072412 = idf(docFreq=3482, maxDocs=42740)
               0.016885111 = queryNorm
             0.5754068 = fieldWeight in 2994, product of:
               3.0 = tf(freq=9.0), with freq of:
                 9.0 = termFreq=9.0
               3.5072412 = idf(docFreq=3482, maxDocs=42740)
               0.0546875 = fieldNorm(doc=2994)
         0.2143656 = weight(abstract_txt:search in 2994) [ClassicSimilarity], result of:
           0.2143656 = score(doc=2994,freq=17.0), product of:
             0.26035568 = queryWeight, product of:
               4.2226744 = boost
               3.6515355 = idf(docFreq=3014, maxDocs=42740)
               0.016885111 = queryNorm
             0.82335675 = fieldWeight in 2994, product of:
               4.1231055 = tf(freq=17.0), with freq of:
                 17.0 = termFreq=17.0
               3.6515355 = idf(docFreq=3014, maxDocs=42740)
               0.0546875 = fieldNorm(doc=2994)
         0.5204391 = weight(abstract_txt:engines in 2994) [ClassicSimilarity], result of:
           0.5204391 = score(doc=2994,freq=14.0), product of:
             0.4799027 = queryWeight, product of:
               5.362715 = boost
               5.2998624 = idf(docFreq=579, maxDocs=42740)
               0.016885111 = queryNorm
             1.0844679 = fieldWeight in 2994, product of:
               3.7416575 = tf(freq=14.0), with freq of:
                 14.0 = termFreq=14.0
               5.2998624 = idf(docFreq=579, maxDocs=42740)
               0.0546875 = fieldNorm(doc=2994)
       0.36 = coord(9/25)
   

4. Zhitomirsky-Geffet, M.; Bar-Ilan, J.; Levene, M.: Testing the stability of "wisdom of crowds" judgments of search results over time and their similarity with the search engine rankings (2016) 0.27

   0.26847768 = sum of:
     0.26847768 = product of:
       0.7457713 = sum of:
         0.023818582 = weight(abstract_txt:large in 5072) [ClassicSimilarity], result of:
           0.023818582 = score(doc=5072,freq=1.0), product of:
             0.09746991 = queryWeight, product of:
               1.2918419 = boost
               4.468454 = idf(docFreq=1331, maxDocs=42740)
               0.016885111 = queryNorm
             0.24436857 = fieldWeight in 5072, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               4.468454 = idf(docFreq=1331, maxDocs=42740)
               0.0546875 = fieldNorm(doc=5072)
         0.014663404 = weight(abstract_txt:that in 5072) [ClassicSimilarity], result of:
           0.014663404 = score(doc=5072,freq=4.0), product of:
             0.05598519 = queryWeight, product of:
               1.3846042 = boost
               2.3946586 = idf(docFreq=10595, maxDocs=42740)
               0.016885111 = queryNorm
             0.26191577 = fieldWeight in 5072, product of:
               2.0 = tf(freq=4.0), with freq of:
                 4.0 = termFreq=4.0
               2.3946586 = idf(docFreq=10595, maxDocs=42740)
               0.0546875 = fieldNorm(doc=5072)
         0.035188057 = weight(abstract_txt:queries in 5072) [ClassicSimilarity], result of:
           0.035188057 = score(doc=5072,freq=1.0), product of:
             0.12643194 = queryWeight, product of:
               1.4713042 = boost
               5.0892105 = idf(docFreq=715, maxDocs=42740)
               0.016885111 = queryNorm
             0.2783162 = fieldWeight in 5072, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               5.0892105 = idf(docFreq=715, maxDocs=42740)
               0.0546875 = fieldNorm(doc=5072)
         0.03713331 = weight(abstract_txt:sets in 5072) [ClassicSimilarity], result of:
           0.03713331 = score(doc=5072,freq=1.0), product of:
             0.1310496 = queryWeight, product of:
               1.4979314 = boost
               5.1813135 = idf(docFreq=652, maxDocs=42740)
               0.016885111 = queryNorm
             0.2833531 = fieldWeight in 5072, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               5.1813135 = idf(docFreq=652, maxDocs=42740)
               0.0546875 = fieldNorm(doc=5072)
         0.05395746 = weight(abstract_txt:known in 5072) [ClassicSimilarity], result of:
           0.05395746 = score(doc=5072,freq=2.0), product of:
             0.13343945 = queryWeight, product of:
               1.511528 = boost
               5.228344 = idf(docFreq=622, maxDocs=42740)
               0.016885111 = queryNorm
             0.4043591 = fieldWeight in 5072, product of:
               1.4142135 = tf(freq=2.0), with freq of:
                 2.0 = termFreq=2.0
               5.228344 = idf(docFreq=622, maxDocs=42740)
               0.0546875 = fieldNorm(doc=5072)
         0.059844308 = weight(abstract_txt:results in 5072) [ClassicSimilarity], result of:
           0.059844308 = score(doc=5072,freq=3.0), product of:
             0.18013932 = queryWeight, product of:
               3.0418582 = boost
               3.5072412 = idf(docFreq=3482, maxDocs=42740)
               0.016885111 = queryNorm
             0.33221126 = fieldWeight in 5072, product of:
               1.7320508 = tf(freq=3.0), with freq of:
                 3.0 = termFreq=3.0
               3.5072412 = idf(docFreq=3482, maxDocs=42740)
               0.0546875 = fieldNorm(doc=5072)
         0.244517 = weight(abstract_txt:rankings in 5072) [ClassicSimilarity], result of:
           0.244517 = score(doc=5072,freq=2.0), product of:
             0.4603972 = queryWeight, product of:
               3.9705935 = boost
               6.8671 = idf(docFreq=120, maxDocs=42740)
               0.016885111 = queryNorm
             0.5311001 = fieldWeight in 5072, product of:
               1.4142135 = tf(freq=2.0), with freq of:
                 2.0 = termFreq=2.0
               6.8671 = idf(docFreq=120, maxDocs=42740)
               0.0546875 = fieldNorm(doc=5072)
         0.13755603 = weight(abstract_txt:search in 5072) [ClassicSimilarity], result of:
           0.13755603 = score(doc=5072,freq=7.0), product of:
             0.26035568 = queryWeight, product of:
               4.2226744 = boost
               3.6515355 = idf(docFreq=3014, maxDocs=42740)
               0.016885111 = queryNorm
             0.5283389 = fieldWeight in 5072, product of:
               2.6457512 = tf(freq=7.0), with freq of:
                 7.0 = termFreq=7.0
               3.6515355 = idf(docFreq=3014, maxDocs=42740)
               0.0546875 = fieldNorm(doc=5072)
         0.13909319 = weight(abstract_txt:engines in 5072) [ClassicSimilarity], result of:
           0.13909319 = score(doc=5072,freq=1.0), product of:
             0.4799027 = queryWeight, product of:
               5.362715 = boost
               5.2998624 = idf(docFreq=579, maxDocs=42740)
               0.016885111 = queryNorm
             0.28983623 = fieldWeight in 5072, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               5.2998624 = idf(docFreq=579, maxDocs=42740)
               0.0546875 = fieldNorm(doc=5072)
       0.36 = coord(9/25)
   

5. Clarke, S.J.; Willett, P.: Estimating the recall performance of Web search engines (1997) 0.26

   0.25698537 = sum of:
     0.25698537 = product of:
       1.0707724 = sum of:
         0.10818731 = weight(abstract_txt:identical in 1761) [ClassicSimilarity], result of:
           0.10818731 = score(doc=1761,freq=1.0), product of:
             0.13366391 = queryWeight, product of:
               1.0697103 = boost
               7.400211 = idf(docFreq=70, maxDocs=42740)
               0.016885111 = queryNorm
             0.80939806 = fieldWeight in 1761, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               7.400211 = idf(docFreq=70, maxDocs=42740)
               0.109375 = fieldNorm(doc=1761)
         0.014663404 = weight(abstract_txt:that in 1761) [ClassicSimilarity], result of:
           0.014663404 = score(doc=1761,freq=1.0), product of:
             0.05598519 = queryWeight, product of:
               1.3846042 = boost
               2.3946586 = idf(docFreq=10595, maxDocs=42740)
               0.016885111 = queryNorm
             0.26191577 = fieldWeight in 1761, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               2.3946586 = idf(docFreq=10595, maxDocs=42740)
               0.109375 = fieldNorm(doc=1761)
         0.10502885 = weight(abstract_txt:sets in 1761) [ClassicSimilarity], result of:
           0.10502885 = score(doc=1761,freq=2.0), product of:
             0.1310496 = queryWeight, product of:
               1.4979314 = boost
               5.1813135 = idf(docFreq=652, maxDocs=42740)
               0.016885111 = queryNorm
             0.8014435 = fieldWeight in 1761, product of:
               1.4142135 = tf(freq=2.0), with freq of:
                 2.0 = termFreq=2.0
               5.1813135 = idf(docFreq=652, maxDocs=42740)
               0.109375 = fieldNorm(doc=1761)
         0.18095672 = weight(abstract_txt:comparing in 1761) [ClassicSimilarity], result of:
           0.18095672 = score(doc=1761,freq=1.0), product of:
             0.2716357 = queryWeight, product of:
               2.641272 = boost
               6.0907364 = idf(docFreq=262, maxDocs=42740)
               0.016885111 = queryNorm
             0.6661743 = fieldWeight in 1761, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               6.0907364 = idf(docFreq=262, maxDocs=42740)
               0.109375 = fieldNorm(doc=1761)
         0.18010314 = weight(abstract_txt:search in 1761) [ClassicSimilarity], result of:
           0.18010314 = score(doc=1761,freq=3.0), product of:
             0.26035568 = queryWeight, product of:
               4.2226744 = boost
               3.6515355 = idf(docFreq=3014, maxDocs=42740)
               0.016885111 = queryNorm
             0.69175804 = fieldWeight in 1761, product of:
               1.7320508 = tf(freq=3.0), with freq of:
                 3.0 = termFreq=3.0
               3.6515355 = idf(docFreq=3014, maxDocs=42740)
               0.109375 = fieldNorm(doc=1761)
         0.48183295 = weight(abstract_txt:engines in 1761) [ClassicSimilarity], result of:
           0.48183295 = score(doc=1761,freq=3.0), product of:
             0.4799027 = queryWeight, product of:
               5.362715 = boost
               5.2998624 = idf(docFreq=579, maxDocs=42740)
               0.016885111 = queryNorm
             1.0040221 = fieldWeight in 1761, product of:
               1.7320508 = tf(freq=3.0), with freq of:
                 3.0 = termFreq=3.0
               5.2998624 = idf(docFreq=579, maxDocs=42740)
               0.109375 = fieldNorm(doc=1761)
       0.24 = coord(6/25)