Study of Query Expansion Techniques and Their Application in the Biomedical Information Retrieval
Table 4
Accuracy of query search using different stemming functions and stopword lists in Cystic Fibrosis. Evaluation measures used are MAP (mean average precision), R-prec (R precision), and (number of relevant documents retrieved).
Combinations
Measures
MAP
R-prec
Baseline
0.1545
0.2098
683
Porter stemmer
0.1663
0.2154
747
Krovetz stemmer
0.1663
0.2231
740
NLM stopword list
0.1681
0.2242
723
SMART stopword list
0.1695
0.2243
728
Porter stemmer-NLM stopwords
0.1790
0.2332
786
Porter stemmer-SMART stopwords
0.1808
0.2342
790
Krovetz stemmer-NLM stopwords
0.1799
0.2333
782
Krovetz stemmer-SMART stopwords
0.1808
0.2324
786
The bold font refers to the best values for the parameters.