Maximising responses to discrete choice experiments: a randomised trial.
OBJECTIVE
To identify any differences in response and completion rates across two versions of a questionnaire, in order to determine the trade-off between a potentially higher response rate (from a short questionnaire) and a greater level of information from each respondent (from a long questionnaire).


METHODS
This was a randomised trial to determine whether response rates and/or results differ between questionnaires containing different numbers of choices: a short version capable of estimating main effects only and a longer version capable of estimating two-way interactions, provided certain assumptions hold. Best-worst scaling was the form of discrete choice experimentation used. Data were collected by post and analysed in terms of response rates, completion rates and differences in mean utilities.


RESULTS
Fifty-three percent of individuals approached agreed to take part. From these, the response to the long questionnaire was 83.2% and the short questionnaire was 85.1% (difference 1.9%, 95% CI -7.3, 11.2; p = 0.68). The two versions of the questionnaire provided similar inferences.


CONCLUSIONS
This trial indicates that, in a healthcare setting, for this complexity of questionnaire (i.e. four attributes and the best-worst scaling design), the use of 16 scenarios obtained very similar response rates to those obtained using half this number.
Coast
Joanna
J
Health Economics Facility, Health Services Management Centre, University of Birmingham, Birmingham, UK. j.coast@bham.ac.uk
Flynn
Terry N
TN
Salisbury
Chris
C
Louviere
Jordan
J
Peters
Tim J
TJ
D002755:Choice Behavior; D006801:Humans; D012107:Research Design; D011795:Surveys and Questionnaires