DIFFERENTIAL VERIFICATION BIAS:
A bias relevant to studies of diagnostic screening. A bias that occurs when an alternative gold standard reference test is given to those subjects in whom the result of the preferred gold standard reference test is not available1,2. Or in other words, intermixing gold standard reference tests and assuming they are the same test in an analysis. Bias results when the two reference tests are of different quality, or they define the target condition differently1.
Differential Verification Bias is related to Workup Bias, and may be considered a type of Verification Bias. Also see: Verification Bias, Workup Bias, Partial Verification Bias, and Spectrum Bias.
References:
1. de Groot JA, Dendukuri N, Janssen KJ, Reitsma JB, Bossuyt PM, Moons KG. Adjusting for differential-verification bias in diagnostic-accuracy studies: a Bayesian approach. Epidemiology. 2011;22(2):234-41. (Link to Reference)
2. Whiting P, Rutjes AW, Reitsma JB, Glas AS, Bossuyt PM, Kleijnen J. Sources of variation and bias in studies of diagnostic accuracy: a systematic review. Ann Intern Med. 2004;140(3):189-202. (Link to Reference)