Importance ratings reflect people's priorities over different aspects of their lives. Some quality of life indices attempt to take into account people's priorities by weighting domain scores with the importance ratings allocated to them in deriving an overall quality of life score. Most indices, however, do not incorporate such ratings, and some researchers argue against their use. At the same time, empirical research on importance ratings has had mixed results. This may be partly because there remain unsettled conceptual questions about importance ratings. This paper addresses some of these questions.