Survey Guidelines


Reliability describes the precision of a measurement. This contribution begins by defining the concept of reliability and explaining why the reliability of a measurement is relevant. It then discusses the model assumptions that must be made in order to estimate the reliability of a measurement, and it presents five methods of estimating reliability: the test-retest method, the parallel-forms method, the split-half method, the internal consistency method, and the estimation of reliability using structural equation modelling. The contribution concludes with a brief outline of the commonalities and differences between classical test theory and the item response theory and the importance of these theories for the estimation of reliability.

English-language version (183 kB)

Version 2.0; doi: 10.15465/gesis-sg_en_011

German-language version (314 kB)

Version 1.1; doi: 10.15465/gesis-sg_011

Earlier version: Version 1.0; doi: 10.15465/sdm-sg_011


Danner, D. (2016). Reliability – The precision of a measurement. GESIS Survey Guidelines. Mannheim, Germany: GESIS – Leibniz Institute for the Social Sciences. doi: 10.15465/gesis-sg_en_0113