Table 1.

Levels of evidence for the overall quality of the measurement property [17]

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	?	Only studies of poor methodological quality

[..] reference number, + positive result, − negative result