Intended for healthcare professionals

Rapid response to:

Endgames Statistical Question

Non-response bias versus response bias

BMJ 2014; 348 doi: (Published 09 April 2014) Cite this as: BMJ 2014;348:g2573

Rapid Response:

The endgame, says in the end that1:

Response bias is one of a group of biases collectively known as ascertainment bias and sometimes referred to as detection bias. Ascertainment bias is the systematic distortion of the assessment of outcome measures by researchers or study participants. This group of biases is a particular problem in clinical trials when the researchers or participants are aware of the treatment allocation1.

I would like to add here that it is also known as measurement bias2. It can be Observer bias or response bias if it is due to systemic error introduced by researcher or participant respectively. This can be minimized in the clinical trial (where it is a particular problem) by "double blinding" the trial.


1. BMJ 2014;348:g2573

2. Basic Epidemiology. 2nd edition. R Bonita, R Beaglehole and Kjellström. World Health Organization, Geneva, p. 55.

Competing interests: No competing interests

02 January 2015
Neeru Gupta
Scientist E
Neeta Kumar, KK Jani.
Indian Council of Medical Research
Ansari Nagar, New Delhi-110029