Abstract
Using either stems or roots as index terms offered considerable performance to Arabic Information Retrieval (IR) systems compared to the use of surface words for indexing. Many comparative works tried to find out the best from these two indexing approaches but until then, no of the two methods widely overtook the other. Each of the two index types performed better under different test circumstances in terms of recall and precision. In this paper, the authors propose a hybrid approach combining the two indexing units in a way they take the advantages from both of them and try to overcome their shortcomings. Then, based on some combining techniques, the authors assign a weight for each indexing unit and try to find out the best weighting values.