Weighted mixed-comparator outcome

Signature

E_mix = sum_(j=1)^J (w_j * E_j)

• 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)
• J Number of mutually exclusive current-care options represented in the mixed comparator (count)

Function

Mixed-comparator construction 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.

  E_mix = (0.70*4.20) + (0.30*4.60) = 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.

Sources

• NICE manual for mixed-comparator outcome

  NICE. Health technology evaluations: the manual. Section 4.6 Economic evaluation.

  View source →

Canonical Identity