CRANV2
Aslib Cranfield Research Project: Factors Determining the Performance of Indexing Systems: Volume 2
Main test results
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.
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FIGURE 4.61 09'
Index Language i, I. a
ExLaustlvity of Indexing 3
Search Ru2e A
Document Relevance 1-4
Number of Documents in Collection
Number of Questions 50
Number of Re!evant Documents 361
Generality Number 5.2
1400
' Coord -
Lrmtion
Level
i
2
3
4
D
6
7
8
9
10
11
12
Documents
Retrieved
Rel. Non-tel.
340 30,778
281 11,572
176 4,717
107 i, 727
59 717
35 273
19 80
7 17
5 2
1 0
0 0
0 0
Recall
Ratio
a/a+c
94.2%
77.8%
48.8%
29.6%
16.3%
9.7%
5.3%
I. 9%
1.4%
0.3%
Precision
Ratio
a/a+b
1.1%
2.4%
3.6%
5.6%
7.0%
11.4%
19.2%
29.2%
71.4%
1 oo. 0%
Fallout
Ratio
b/b+d
44.196%
16.017%
6.759%
2.48o%
I. 015%
0. 392%
0,115%
0. 024%
0.003%
0. 000%
FIGURE 4.011T
Index Language I. 1. a
Exhaustivity of Indexing 3
Search Rule A
Document Relevance 1-3
Number of Documents in Collection 1400
Number of Questions 50
Number of Relevant Documents 297
GeneraLity Number 4.2
I ;
3
4
5
6
7
8
9
10
11
12
Documents
Retrieved
Rel.
277
235
i02
97
49
20
"16
6
4
1
0
0
Non-rel.
30,041 93.2%
11,618 79.1%
4,731 54.5%
1,737 32.7%
724 16.5%
279 9.8%
83 5.3%
10 2.0%
3 1.3%
0 0.3%
0
0
Recall
Ratio
a/a+e
Precision
Ratio
a]a+b
o. 0%
2.0%
3.4%
5.3%
6.4%
9.2%
16.2%
26.0%
57.1%
1 00. O%
Fallout
Ratio
b/b+d
44. 246[OCRerr]
16.651%
6. 787%
2.492%
1. 039%
O. 400%
0.119%
O. 026%
o. 004%
o. 000%
5O
50
47
39
21
12
8
4
3
1
0
0
50 50 50
50 50 50
47 50 50
39 46 46
21 40 40
12 30 30
8 23 23
4 12 12
3 I0 I0
1 6 8
0 6 6
0 l 11
50
50
50
46
40
30
23
12
i0
0
6
1
50
5O
50
46
4O
30
23
12
10
8
6
1
!