Jadad Scale - Jadad Questionnaire

Jadad Questionnaire

In an appendix to their 1996 paper, Jadad et al. published a three-point questionnaire that formed the basis for a Jadad score. Each question was to be answered with either a yes or a no. Each yes would score a single point, each no zero points; there were to be no fractional points. The Jadad team stated that they expected it should take no longer than ten minutes to score any individual paper. The questions were as follows:

1. Was the study described as randomized?
2. Was the study described as double blind?
3. Was there a description of withdrawals and dropouts?

To receive the corresponding point, an article should describe the number of withdrawals and dropouts, in each of the study groups, and the underlying reasons. Additional points were given if:

• The method of randomisation was described in the paper, and that method was appropriate.
• The method of blinding was described, and it was appropriate.

Points would however be deducted if:

• The method of randomisation was described, but was inappropriate.
• The method of blinding was described, but was inappropriate.

A paper reporting a clinical trial could therefore receive a Jadad score of between zero and five. The Jadad scale is sometimes described as a five-point scale, though there are only three questions.