A base case analysis usually refers to the results obtained from running an economic model with the most likely or preferred set of assumptions and input values. Sensitivity analyses may then be used to explore how the results deviate from those of the base case analysis when input values and/or modelling assumptions are altered. ‘Reference case’ (analysis) may be used as an alternative to base case analysis. Reference case analyses are especially used where analysts are directed to a standard set of modelling assumptions by a health technology assessment (HTA) organisation such as the National Institute for Health and Care Excellence (NICE).