Table 7.

Levels of evidence for the overall quality of the measurement property [18–21]

Level	Rating	Criteria
Strong	+++ or ---	Consistent findings in multiple studies of good methodological quality OR in one study of excellent methodological quality
Moderate	++ or -	Consistent findings in multiple studies of fair methodological quality OR in one study of good methodological quality
Limited	+ or –	One study of fair methodological quality
Conflicting	+/−	Conflicting findings
Unknown	x	Studies of poor methodological quality and studies with indeterminate quality of measurement properties