Although it has been shown that in test collection based studies,\ud stemming improves retrieval effectiveness in an information retrieval system,\ud morphological variations of queries searching on the same topic are less well\ud understood. This work examines the broad morphological variation that\ud searchers of an Arabic retrieval system put into their queries. In this study, 15\ud native Arabic speakers were asked to generate queries, morphological variants\ud of query words were collated across users. Queries composed of either the\ud commonest or rarest variants of each word were submitted to a retrieval system\ud and the effectiveness of the searches was measured. It was found that queries\ud composed of the more popular morphological variants were more likely to\ud retrieve relevant documents that those composed of less popular.