Lexical and algorithmic stemming compared for 9 European languages with hummingbird searchserverTM at CLEF 2003

Abstract

Hummingbird participated in the monolingual information retrieval tasks of the Cross-Language Evaluation Forum (CLEF) 2003: for natural language queries in 9 European languages (German, French, Italian, Spanish, Dutch, Finnish, Swedish, Russian and English), find all the relevant documents (with high precision) in the CLEF 2003 document sets. SearchServer produced the highest mean average precision score of the submitted automatic Title+Description runs for German, Finnish and Dutch, the CLEF languages for which SearchServer could find words which are parts of compounds. In a comparison of experimental SearchServer lexical stemmers with Porter's algorithmic stemmers, the biggest differences (most of them significant) were for languages in which compound words are frequent. For the other languages, typically the lexical stemmers performed inflectional stemming while the algorithmic stemmers often additionally performed derivational stemming; these differences did not pass a significance test. © Springer-Verlag 2004.