VOI analysis holds great promise to improve our interpretation of the findings of a health economic evaluation and help plan further work — indeed, it is being declared mandatory in some jurisdictions. There is a great risk, however, that rushing headlong to implement it, will seriously mislead decision makers and research funding. In this paper, some of the key challenges will be reviewed, with particular focus on the elements that are not being discussed: components that may bear the largest uncertainty such as the structure of the underlying model, the choice of modeling technique and the way in which the core control parameters are formulated and estimated.