Table 2.

Criteria for quality assessment, based on the criteria for quality assessment from the Swedish Council on Technology Assessment in Health Care (SBU) [10]

Design*	I=High	II=Medium	III=Low
RCT	Large and well accomplished multi-center study with sufficient descriptions of protocol, material, and methods. Enough sample size to answer the questions at issue.	neither high nor low	Sample size too small and/or too many interventions to give enough statistical power. Indistinctly described and high participant drop-out rate.
CCT	Well defined questions at issue, sufficient sample size and adequate statistics.	neither high nor low	Small sample size and questionable statistical methods.
DS	Large and well defined consecutive sample analyzed with adequate statistics, long follow-up.	neither high nor low	Small sample size, indistinctly described, follow-up too short, or inadequate statistics.
Q	Well defined questions at issue. Relevant and well described selection, data collection, and analysis. Logically and understandable interpretations and conclusions. Good communicability and conclusions.	neither high nor low	Insufficiently defined questions at issue, selection indistinctly described. Insufficiently described data collection, analysis, interpretations, and conclusions. Indistinct communicability and conclusions.

^*RCT = randomized controlled trial, CCT=quasi controlled trial, DS=descriptive study, Q=qualitative study.