Signature
E_mix = sum_(j=1)^J (w_j * E_j)
| Inputs | Definition | Unit |
|---|---|---|
w_j | Proportion of the comparator population receiving current-care option j | proportion |
E_j | Expected outcome of current-care option j | the common outcome measure |
E_mix | Treatment-share-weighted expected outcome of the mixed comparator | the common outcome measure |
|---|
JNumber of mutually exclusive current-care options represented in the mixed comparator (count)
Function
Mixed-comparator construction function
Maps the treatment shares and expected results of current-care options to a weighted mixed comparator.
Try this function
Implementations
Excel
Calculate weighted comparator outcome
Excel multiplies each option outcome by its treatment share and adds the products.
=SUMPRODUCT(TreatmentShares,OptionOutcomes)
Assumptions
Valid treatment shares for outcome weighting
Treatment shares are non-negative and sum to 1 across the mutually exclusive comparator options.
Common outcome measure for mixed comparator
Every comparator option uses the same outcome definition, unit and timing convention.
Representative current practice for outcome weighting
Treatment shares reflect the expected comparator mix for the relevant population, setting and period.
Worked examples
Weighted comparator outcome
Current care consists of Option A for 70% of patients with 4.20 QALYs and Option B for 30% with 4.60 QALYs. Mixed-comparator outcome is 4.32 QALYs.
J = 2; w_j = [0.70,0.30]; E_j = [4.20,4.60]; E_mix = 4.32
Common errors
Mixing incompatible outcome measures
Options measured with different outcome definitions, instruments or time horizons cannot be combined into a meaningful weighted comparator outcome.
Averaging options that are separate choices
When the comparator options are mutually exclusive choices open to the decision-maker, a weighted mix hides the incremental comparisons between them. Each option should instead enter a fully incremental analysis, and the new intervention is judged against the adjacent non-dominated option.
Sources
NICE manual on comparators and fully incremental analysis
National Institute for Health and Care Excellence. NICE technology appraisal and highly specialised technologies guidance: the manual (PMG36). Published 31 January 2022, last updated 13 October 2026. Sections 4.2.5 (comparators as defined in the scope) and 4.10.8 (fully incremental analysis).
Canonical Identity
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