Relevance and Other Basic Problems

Relevance is the central evaluation criterion in information retrieval evaluation. Search and discovery services yielding relevant responses to queries now constitute an important industry. Indirectly (through bibliometrics) relevance indicators are increasingly the basis for academic evaluations. Yet, even though relevance has been considered a central concept in information science for fifty years and closely examined, there is still no satisfactory definition or explanation. Why is this? I will draw on recent seminar discussions to explore and try to explain this and other basic problems in understanding information.