Hornbaek, K. and Law, E.L-C. (2007) Meta-analysis of correlations among usability measures. In Proceedings of the SIGCHI Conference on Human Factors in Computing Systems (CHI ’07). ACM, New York, NY, USA, pp. 617-626.
Hornaek and Law repeated a similar meta-analysis as Nielsen and Levy (1994) on usability studies reported in top HCI conferences and journals. They studied the data from 73 usability studies and analysed correlations between various usability measures, such as effectiveness, efficiency and satisfaction. In contradiction to the results by Nielsen and Levy, Hornbaek and Law found only medium to low correlation among usability measures.
As they studied the material, they also noticed that homegrown questionnaires were less reliable, and therefore recommend to use standard questionnaires if possible.