Table 2.

Study Quality Ratings

Topic	Year	Author	Study Design	Internal Validity	External Validity	QHES Rating
Care Models	2010	Gordon et al.(22)	Case Control	High	High	64.0 (Fair Quality)
Prosthetic Treatment	2007	Mackenzie et al. (23)	Case Control‡	Low	High	77.0 (High Quality)
Prosthetic Treatment	2010	Gil et al. (24)	Case Control	Low	High	62.5 (Fair Quality)
Prosthetic Sockets	2004	Datta et al. (25)	Randomized Controlled Trial	Mod	High	69.0 (Fair Quality)
Prosthetic Sockets	2005	Selles et al. (26)	Randomized Controlled Trial	Mod	High	57.5 (Fair Quality)
Prosthetic Sockets	2011	Normann et al. (27)	Controlled Trial	Mod	High	65.5 (Fair Quality)

QHES is Quality of Health Economic Studies.

^‡Mackenzie et al. used a cost-identification design whereas all others used a cost-consequence design.