Terminology
NICE reference case
NICE's manuals outline the methods that it considers most appropriate for estimating clinical effectiveness and value for money. Health economic modelling teams should follow these methods, referred to as the reference case in NICE's health technology evaluation manual (and cross-referred to in NICE's guidelines manual). For example, the reference case specifies that, in most cases, the quality-adjusted life year should be used as the measure of overall health gain.
Disease-specific reference case extension
Disease-specific reference case extensions are extensions to the existing NICE reference case. A disease-specific reference case extension specifies the characteristics a model should have in a specific disease area or condition, rather than providing a fully implemented model. The level of detail will vary by disease and could include any of the following:
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lists of outcomes (including adverse events), comparator treatment strategies and population subgroups to be captured
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a conceptual model containing the specific relationships between different health states and outcomes
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specific input assumptions and datasets to be used.
The aim of a reference case extension at NICE is to signal what NICE considers current best practice in how an economic analysis for a particular disease should be designed. It should be used for all guidance development for a specific disease or condition unless there are strong justifications not to.
The term should not be shortened to 'reference case' unless it is clear from the context that it is the disease-specific reference case extension that is being referred to.
Disease-specific reference model
Disease-specific reference models evaluate a wide set of interventions within a particular disease area or condition (adapted from Haji Ali Afzali and Karnon 2011). These are developed independently of the companies, populated using best available evidence and validated. They are executable models that are available to companies submitting health technologies for assessment by health technology assessment (HTA) bodies and guideline developers.