Examining the Relationship Between the NICE WTP Threshold and the Severity Modifier
Author(s)
Simone Critchlow, MSc1, Cameron Lilley, MSc2, Rachael Batteson, MSc1.
1Petauri Evidence, Nottingham, United Kingdom, 2HEOR, Cardiff, United Kingdom.
1Petauri Evidence, Nottingham, United Kingdom, 2HEOR, Cardiff, United Kingdom.
OBJECTIVES: The introduction of severity-based weighting by the National Institute for Health and Care Excellence (NICE) was intended to enable higher willingness-to-pay (WTP) thresholds for interventions treating more severe conditions. This research evaluates how the severity modifier, introduced in February 2022, has influenced stated WTP thresholds for decision-making in published technology appraisals (TAs).
METHODS: A targeted review of the NICE website was conducted to identify TAs published between February 2022 and February 2025 that referenced the severity modifier. Data were extracted on the applied severity weighting (1.2x or 1.7x) and the WTP threshold (explicitly stated or implied) in each appraisal.
RESULTS: In 35 cases, NICE considered application of a severity modifier to be appropriate. A 1.2x and 1.7x severity modifier were applied in 24 (69%) and 11 (31%) instances, respectively. In 14% of cases where a severity modifier was applied, a WTP threshold of £20,000 or below was cited (with a further 17% determined as being at the ‘lower end of the threshold’). In only 20% of cases where a modifier was applied, a £30,000 threshold was cited. In one instance, a 1.2x modifier was applied to a threshold between £30,000-£35,000 (due to both severity and the presence of health inequalities).
CONCLUSIONS: Although, in theory, the introduction of the severity modifier offers greater flexibility to recommend technologies through a higher overarching threshold, evidence suggests that even when meeting the eligibility criteria for a severity modifier, a substantial proportion of appraisals are being evaluated within the conventional threshold range (£20,000-£30,000). This is because the weighting is often being applied to a pre-specified WTP at the lower end of the standard range. Further investigation is warranted to assess the consistency, transparency, and policy implications of the use of the severity modifier and its interaction with greater specificity in stated WTPs within NICE appraisals.
METHODS: A targeted review of the NICE website was conducted to identify TAs published between February 2022 and February 2025 that referenced the severity modifier. Data were extracted on the applied severity weighting (1.2x or 1.7x) and the WTP threshold (explicitly stated or implied) in each appraisal.
RESULTS: In 35 cases, NICE considered application of a severity modifier to be appropriate. A 1.2x and 1.7x severity modifier were applied in 24 (69%) and 11 (31%) instances, respectively. In 14% of cases where a severity modifier was applied, a WTP threshold of £20,000 or below was cited (with a further 17% determined as being at the ‘lower end of the threshold’). In only 20% of cases where a modifier was applied, a £30,000 threshold was cited. In one instance, a 1.2x modifier was applied to a threshold between £30,000-£35,000 (due to both severity and the presence of health inequalities).
CONCLUSIONS: Although, in theory, the introduction of the severity modifier offers greater flexibility to recommend technologies through a higher overarching threshold, evidence suggests that even when meeting the eligibility criteria for a severity modifier, a substantial proportion of appraisals are being evaluated within the conventional threshold range (£20,000-£30,000). This is because the weighting is often being applied to a pre-specified WTP at the lower end of the standard range. Further investigation is warranted to assess the consistency, transparency, and policy implications of the use of the severity modifier and its interaction with greater specificity in stated WTPs within NICE appraisals.
Conference/Value in Health Info
2025-11, ISPOR Europe 2025, Glasgow, Scotland
Value in Health, Volume 28, Issue S2
Code
HTA143
Topic
Economic Evaluation, Health Technology Assessment
Topic Subcategory
Decision & Deliberative Processes, Value Frameworks & Dossier Format
Disease
No Additional Disease & Conditions/Specialized Treatment Areas