CRANV2 Citation indexing and bibliographic coupling chapter Cyril Cleverdon Michael Keen Cranfield An investigation supported by a grant to Aslib by the National Science Foundation. Use, reproduction, or publication, in whole or in part, is permitted for any purpose of the United States Government. 245 FIGURE 7.2T Index Language Citation Indexing and Bibliographic Coupling Document Relevance 1-4 Number of Documents in Collection 1400 Number of Questions 42 (Subset 2 Aerodynamics) Number of Relevant Documents 198 Generality Number 3.4 ....................................... "[OCRerr] ............ -i- ............= .................. Coupling Documents Recall Precision Fallout Strength 1 2 3 4 5 6 7+ Retrieved Rel. Non -rel. 131 5495* 113 1446 76 592 56 257 41 135 29 70 23 38 R at io 66.1% 56.3% 38.2% 28.1% 20.6% 14.6% 11.6% Ratio 2.3%* 7.2% 11.47° 17.9% 23.3% 29.3% 37.7% Ratio 9. 345%* 2.459% i. 0077o 0.437% 0.2307° 0. 119% 0. 065% FIGURE 7.3T Index Language Citation Indexing and Bibliographic Coupling Document Relevance 1-4 Number of Documents in Collection 1400 Number of Questions 42 (Structures) Number of Relevant Questions 252 Generality Number 4.3 Coupling Strength l. 2 3 4 5 6 7+ Documents Retrieved Rel. Non -rel. 179 5962* 138 1569 90 541 51 140 36 93 31 54 25 28 Recall Ratio 71.0% 54.8% 35.7% 20. {% 14.3% 12.3% 9.970 Precision Ratio 2.9%* 8.1% 14.3% 26.7% 27.9% 36.5% 47. 270 Fallout Ratio 10. 684%* 2.668% 0. 920% 0. 238% 0. 193% 0.09270 0.047%