The Cranfield experiments were experiments conducted by Cyril W. Cleverdon  at Cranfield University

Cranfield University

Cranfield University is a British postgraduate university based on two campuses, with a research-oriented focus. The main campus is at Cranfield, Bedfordshire and the second is the Defence Academy of the United Kingdom based at Shrivenham, Oxfordshire. The main campus is unique in the United...

 in the 1960s to evaluate the efficiency of indexing systems. They represent the prototypical evaluation model of information retrieval

Information retrieval

Information retrieval is the area of study concerned with searching for documents, for information within documents, and for metadata about documents, as well as that of searching structured storage, relational databases, and the World Wide Web...

 systems, and this model has been used in large-scale information retrieval evaluation efforts such as the Text Retrieval Conference

Text Retrieval Conference

The Text REtrieval Conference is an on-going series of workshops focusing on a list of different information retrieval research areas, or tracks. It is co-sponsored by the National Institute of Standards and Technology and the Intelligence Advanced Research Projects Activity , and began in 1992...

(TREC).