Since there are many authors from the community who author the documents, there are many different terms that can be used to describe the same thing. Also, slight distinctions in meaning that may be made by an author may not be clear to someone searching the dataset. The thesaurus can be used to encompass these distinctions in meaning. Results from these expanded searches generally have higher recall and somewhat lower precision. Higher recall means that more or the desired species descriptions are returned when a query is processed.
Precision is a measure of how many of the returned documents are indeed relevant.
As the search is broadened, some number of irrelevant documents creep into the result set. The size of the collection, the variability of the document vocabulary and the vocabulary of the searchers all play a role in determining if automatic query expansion helps with the task that they are trying to perform. In this project we will evaluate the effectiveness of this technique for the flora's user community for different tasks. The effectiveness of any of these thesaurus enhancing techniques is dependent on many parameters related to the people who are going to use the system and the tasks that they are going to perform. It is therefor important to evaluate the proposed features, in the context of their intended use.