Spørringsutvidelser

Spørringsutvidelser, also known as query expansions, are techniques used in information retrieval systems to improve search results. The core idea is to reformulate a user's original query to include related terms or concepts that might not have been explicitly present in the initial search. This expansion aims to broaden the search space and increase the likelihood of finding relevant documents, especially when users are uncertain about the exact terminology or when synonyms and related terms are crucial for a comprehensive search.

There are several common methods for query expansion. Lexical expansion involves using thesauri or dictionaries to substitute query terms with synonyms or related words. For example, a search for "car" might be expanded to include "automobile" or "vehicle." Concept-based expansion goes a step further by identifying broader or narrower concepts related to the query terms. This could involve using ontologies or knowledge graphs to link terms. Another approach is query-dependent expansion, where terms from initially retrieved highly relevant documents are added to the original query to refine the search. Statistical methods, such as term co-occurrence analysis, can also be employed to identify terms that frequently appear together, suggesting they are semantically related.

The effectiveness of query expansion depends heavily on the quality of the expansion resources and the specific retrieval task. While it can significantly improve recall by retrieving more relevant documents, it can also potentially decrease precision if irrelevant terms are introduced, leading to the retrieval of less pertinent information. Therefore, query expansion techniques often incorporate mechanisms to manage the balance between recall and precision, such as limiting the number of expanded terms or assigning weights to them.