Concept Architecture
Concept
Theoretically, Direct Elicitation is a preference elicitation approach used to obtain individual valuations of health states directly from respondents rather than indirectly through descriptive health status instruments. It is grounded in utility theory and preference measurement, enabling individuals to express the value they assign to specific health outcomes using structured valuation techniques. Direct elicitation exists to generate health state utility values for use in economic evaluation and decision analysis.
Mathematically, Direct Elicitation is represented through the formal decision rules underlying the elicitation technique employed. Depending on the method, utility values are derived from choices involving probabilities (Standard Gamble), time trade-offs (Time Trade-Off), or direct rating scales (Visual Analogue Scale). These mathematical frameworks transform respondent preferences into utility scores, typically anchored on 0 for death and 1 for full health, although some methods permit values below 0 for states considered worse than death.
In practice, Direct Elicitation is undertaken using structured interviews, questionnaires or computer-assisted surveys with patients, members of the public or expert respondents. The resulting utility estimates are analysed statistically, summarised across respondents and incorporated into cost-utility analyses, decision-analytic models and health technology assessments.
Purpose
Used to measure health state preferences directly from respondents, derive utility values for quality-adjusted life year estimation, support cost-utility analysis, develop preference weights and inform healthcare resource allocation.
Mathematical Formulae
Primary Formula
There is no universally recognised canonical mathematical formula.
Supporting Formulae
Standard Gamble
U(H) = p
where:
- U(H) = utility of health state H
- p = probability of full health at the point of indifference
Time Trade-Off
U(H) = t / T
where:
- t = years in full health considered equivalent
- T = years in the impaired health state
Related Mathematical Methods
- Standard Gamble
- Time Trade-Off
- Visual Analogue Scale
- Utility theory
- Preference elicitation
- Expected utility theory
Example
A respondent is indifferent between living 10 years with a chronic health condition or 8 years in full health.
Using the Time Trade-Off method:
U = 8 / 10 = 0.80
The directly elicited utility for the chronic health state is therefore 0.80, which may subsequently be used to calculate QALYs in a cost-utility analysis.
Excel Implementation
| Function | Example Formula | Health Economics Application |
|---|---|---|
/ | =B2/C2 | Calculates Time Trade-Off utility from equivalent years in full health. |
| AVERAGE | =AVERAGE(D2:D101) | Calculates the mean utility across respondents. |
| SUMPRODUCT | =SUMPRODUCT(UtilityRange,TimeRange) | Calculates QALYs using directly elicited utility values. |
| STDEV.S | =STDEV.S(D2:D101) | Estimates variation in elicited utility values. |
VBA (Optional)
Automate the calculation, validation and reporting of directly elicited utility values from respondent survey datasets.
Sources
- Torrance GW. Measurement of Health State Utilities for Economic Appraisal. Journal of Health Economics.
- Drummond MF, Sculpher MJ, Claxton K, Stoddart GL, Torrance GW. Methods for the Economic Evaluation of Health Care Programmes. Oxford University Press.
- Briggs A, Claxton K, Sculpher M. Decision Modelling for Health Economic Evaluation. Oxford University Press.
- Gold MR, Siegel JE, Russell LB, Weinstein MC (Eds.). Cost-Effectiveness in Health and Medicine.
- NICE. Health Technology Evaluation Manual.
Related Concepts (2)
Library
Publications
1
Measuring and Valuing Health Benefits for Economic Evaluation — Brazier, Ratcliffe, Salomon & Tsuchiya, 2nd Edition ed., 2017 (Oxford University Press)
The comprehensive text on the measurement and valuation of health benefits for economic evaluation — defining health, valuation techniques (time trade-off, standard gamble), whose values to use, preference-based measures (EQ-5D, SF-6D), and the construction of QALYs.
BookView source →
Frequently Asked Questions (6)
What is direct elicitation?
A health state valuation approach in which respondents value a state directly, using techniques such as the standard gamble or time trade-off.
Source: Torrance GW. Measurement of health state utilities for economic appraisal. Journal of Health Economics. 1986;5(1):1-30. doi:10.1016/0167-6296(86)90020-2.
What is direct elicitation of health state utilities?
Direct elicitation is a valuation approach in which respondents value a health state directly, using techniques such as the standard gamble or the time trade-off, rather than inferring the value from responses to a descriptive questionnaire. The respondent is presented with the state and asked to make a choice or trade-off that reveals its utility. This contrasts with indirect approaches, in which a value is assigned by applying a pre-existing value set to a described state.
Source: Torrance 1986
How does direct elicitation work?
In direct elicitation, a respondent is presented with a described health state and asked to value it through a task such as the standard gamble, choosing between the certain state and a gamble on full health or death, or the time trade-off, giving up length of life for full health. The point of indifference reveals the utility of the state. The value comes directly from the respondent's own trade-off rather than from a scoring formula.
Source: Torrance 1986
When is direct elicitation used?
Direct elicitation is used when values are needed for specific health states not covered by an existing instrument, when the study seeks values from a particular group such as patients, or when developing the value set that indirect methods later apply. It is more demanding to administer than applying a questionnaire, so it is used where direct valuation is required rather than for routine measurement, for which indirect instruments are usually more practical.
Source: Torrance 1986
What are the limitations of direct elicitation?
Direct elicitation is demanding and time-consuming, requiring respondents to complete valuation tasks that they may find difficult, so it is impractical for measuring many patients routinely. The values depend on the technique used, since the standard gamble and time trade-off can give different results, and on how the states are described. It also requires trained administration. These features make it less suited to routine data collection than indirect instruments with established value sets.
Source: Torrance 1986
How does direct elicitation differ from indirect valuation?
Direct elicitation obtains a utility by having the respondent value the state through a trade-off task, while indirect valuation has the respondent describe their health on a questionnaire, and a pre-existing value set assigns the utility. Direct elicitation values the specific state as experienced or imagined by the respondent; indirect valuation applies population preferences to a described state. The indirect approach is more practical for routine use, while direct elicitation is used where bespoke values are required.
Source: Torrance 1986
Trust Record
Verified by Dr Darrin Baines
British health economist
Professional identity: darrinbaines.org
Verification date: 28 Aug 2025
Content version: 1.0.0
Canonical Identity
- Persistent URI
- https://healtheconomics.wiki/concept/direct-elicitation
- Term code
- HE-EE-HU-016
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