The following results were reported at the 2001 IHM-HCI conference in Lille, France.

The Global Usability Score (GUS) exhibits a high degree of reliability, technically measured using Cronbach's Alpha coefficient, with Alpha = 0.90. This coefficient usually ranges from 0.00 (poor reliability) to 1.00 (high reliability).

The five sub-scales, being smaller, have lower intrinsic Alpha coefficients, but when adjusted for size, are comparable with the Global scale:

Scale	Reliability
	Raw	Adj.
Attractiveness	0.640	0.899
Controllability	0.690	0.918
Efficiency	0.630	0.895
Helpfulness	0.700	0.921
Learnability	0.740	0.934
Global	0.900	-