Cost-effectiveness analysis used by NICE is essentially an assessment of whether the health expected to be gained from the use of a new medical technology exceeds the health likely to be forgone as other NHS activities are displaced to accommodate the additional costs of the new technology. The cost-effectiveness threshold represents an estimate of the health forgone as services are displaced. Currently the threshold used by NICE has little empirical basis. The aim of this new research project is to develop and to demonstrate methods for threshold estimation which make best use of routinely available NHS data, allowing scrutiny by a range of stakeholders, improving accountability and predictability. This research will focus on complementary methods which can make best use of those data that are already available, where there are already plans to make data available or where additional data could feasibly be made available at reasonable cost.