Thanks for the suggestions I think Erick is correct as well. I'll let the customer decide.
Here's an updated list. Fyi--the minStem was the English Minimal Stemmer--I changed the label. Interesting to see where the minimal stemmer and porter agree (and KStemmer doesn't). You may also find the "dog" examples interesting. I also found the "invest*" list entertaining. original porter kstem EngMinStem ----------- ----------- ----------- ----------- country countri country country countries countri country country country's country' country's country' run run run run runs run runs run running run running running read read read read reading read reading reading reader reader reader reader association associ association association associate associ associate associate listing list list listing water water water water watered water water watered sure sure sure sure surely sure surely surely invest invest invest invest investing invest invest investing investment invest investment investment investments invest investment investment invests invest invest invest investor investor invest investor invester invest invest invester investors investor invest investor investers invest invest invester organization organ organization organization organize organ organize organize organic organ organic organic generous gener generous generous generic gener generic generic dog dog dog dog dog's dog' dog's dog' dogs dog dogs dog dogs' dog dogs dog Now, if someone would answer my question on the Solr list ("Custom Solr Indexer/Search"), my day would be complete ;-). Thanks for the continued help. Scott -----Original Message----- From: Tom Burton-West [mailto:tburt...@umich.edu] Sent: Thursday, November 15, 2012 11:06 AM To: java-user@lucene.apache.org Subject: Re: Which stemmer? I agree with Erick that you probably need to give your client a list of concrete examples, and perhaps to explain the trade-offs. All stemmers both overstem and understem. Understemming means that some forms of a word won't get searched. For example, without stemming, searching for "dogs" would not retrieve documents containing the word "dog". Generally there is a precision/recall tradeoff where reducing understemming increases overstemming. The problem with aggressive stemmers like the Porter stemmer, is that they overstem. The original Porter stemmer for example would stem "organization" and " organic" both to "organ" and "generalization" , "generous"and "generic" to " gener" * For background on the Porter stemmers and lots of examples see these pages: http*://snowball.tartarus.org/algorithms/porter/stemmer.html<http://snowball.tartarus.org/algorithms/porter/stemmer.html> * *http://snowball.tartarus.org/algorithms/english/stemmer.html*<http://snowball.tartarus.org/algorithms/english/stemmer.html> This paper on the Kstem stemmer lists cases where the Porter stemmer understems or overstems and explains the logic of Kstem: "Viewing Morphology as an Inference Process" (*Krovetz*, R., Proceedings of the Sixteenth Annual International ACM SIGIR Conference on Research and Development in Information Retrieval, 191-203, 1993). *http://ciir.cs.umass.edu/pubfiles/ir-35.pdf*<http://ciir.cs.umass.edu/pubfiles/ir-35.pdf> " Tom http://www.hathitrust.org/blogs/large-scale-search --------------------------------------------------------------------- To unsubscribe, e-mail: java-user-unsubscr...@lucene.apache.org For additional commands, e-mail: java-user-h...@lucene.apache.org