* An "X" indicates an area explored; a
blank space indicates it was not addressed by the study.
Dimensions of quality explored by different
scales*
Scale and study
No. of levels
Study design
Quality of conduct
Consistency of results
Canadian Task Force, 19903
4
X
US Preventive Services Task Force,
19964
5
X
AHCPR, 199211
5
X
Guyatt et al., 199512
6
X
X
Eccles et al, 199610
6
X
Hadorn et al, 199613
7
X
X
Ball et al, 199714
10
X
X
X
Liddle et al, 199715
5
X
X
X
Jovell et al, 199716
9
X
X
X
AHCPR = Agency for Health
Care Policy and Research.