Jadad score

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In epidemiology and biostatistics, the Jadad score is used to assess the quality of a randomized controlled trial. The score was first published in 1996 by Dr. Alejandro Jadad.[1]


The score contains three items:

  1. Was the study described as randomized (this includes the use of words such as randomly, random, and randomization)?
  2. Was the study described as double blind?
  3. Was there a description of withdrawals and dropouts? "For a positive answer, the number of withdrawals and dropouts and the reasons had to be stated in each of the comparison groups."

Each question is scored one point for a yes answer.

In addition, for questions 1 and 2, a point is added if the method was appropriate and a point is deducted if the method is not appropriate:

  • "A method to generate randomization sequences was regarded as adequate if it allowed each study participant to have the same chance of receiving each intervention, and if the investigators could not predict which intervention was next."
  • "Double blinding was considered appropriate if it was stated or implied that neither the person doing the assessment nor the study participant could identify the intervention being assessed."

Examples of use in meta-analysis

There are many examples of use of the Jadad score in meta-analysis. Cut-offs for high quality may include a Jadad score of 3 or more.[2]


  1. Jadad AR, Moore RA, Carroll D, et al (1996). "Assessing the quality of reports of randomized clinical trials: is blinding necessary?". Control Clin Trials 17 (1): 1–12. DOI:10.1016/0197-2456(95)00134-4. PMID 8721797. Research Blogging.
  2. Zoungas S, Ninomiya T, Huxley R, Cass A, Jardine M, Gallagher M et al. (2009). "Systematic review: sodium bicarbonate treatment regimens for the prevention of contrast-induced nephropathy.". Ann Intern Med 151 (9): 631-8. DOI:10.1059/0003-4819-151-9-200911030-00008. PMID 19884624. Research Blogging.