iDSI Reference Case for Economic Evaluation

The iDSI Reference Case is a principle-based approach to guide the planning, conduct and reporting of economic evaluations. It provides decision makers with relevant and reliable ways to determine the likely implications of implementing a treatment or health service in specific contexts. Its primary focus is on meeting the informational needs of decision makers in low- and middle-income countries (LMICs). It builds on the methods and approaches of the National Institute for Health and Care Excellence (NICE) in the UK, the Health Intervention and Technology Assessment Program (HITAP) in Thailand and the World Health Organization, the iDSI Reference Case helps countries to calculate value for money and to consistently spend their health budgets effectively.

Some of the biggest decisions that must be made within health systems are on how to spend the health budget. These unavoidable decisions will have large consequences. Understanding the expected clinical effect of differing health treatments and services, and how much it will cost to achieve that clinical effect, is called determining the value. When people know the value of the different options, decision making becomes easier and money can be spent more effectively on health.

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Using the reference case

The iDSI reference case is an aid to thinking. It provides a systematic way in which to conduct and report on economic evaluations, but also the flexibility to tailor the methodology to specific needs and setting.

The principles of the iDSI reference case describe how to undertake economic evaluations that are fit for purpose, but don’t specify particular metrics or parameter values. The methodological specifications are a non-exhaustive set of options that enable the economic evaluation to adhere to the principles. These principles each contain a suggested implementation methodology and guidance for reporting.

The principles


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Measurement of Outcome

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Measurement of Costs

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Time Horizon

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Costs and Effects Outside of Health

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Budget (and other) Impacts

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Equity Implications

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Related research

The IDSI Reference Case initiative has provided a foundation for a body of economic evaluation methods research that are of particular importance for policymaking:

1. Assessing relevant evidence for economic evaluation and decision-making (linked to Principle 3: Perspective)
2. Reflecting non-budgetary constraints in economic evaluation (linked to Principle 10: Budget impact and other constraints)
3. The choice of cost-effectiveness thresholds to inform decision-making (Standalone topic also linked to Principle 10)

In order to investigate these methods topics in greater detail and provide guidance to analysts and policymakers, the iDSI Methods Working Groups were established in a collaboration between the University of Glasgow and the London School of Hygiene and Tropical Medicine (leading work on assessing relevant evidence); Erasmus University, Rotterdam (leading on reflecting non-budgetary constraints; particularly human resource constraints); and the Centre for Health Economics, University of York (leading on the choice of cost-effectiveness thresholds).

The findings from the iDSI Methods Working Groups are presented in the following reports:

These reports are intended to be guides to the conduct and use of economic evaluation studies and are not intended to be prescriptive or to restrict the use and development of other types of methods that may also adhere to the Principles.

On-going research

Within-country threshold estimation: Indonesia

Led by Marc Suhrcke (University of York), within-country analysis is being conducted to determine cost-effectiveness thresholds in LMICs. Related publications and reports to date include:

Exploration of non-budgetary constraints in a LMIC setting

Peter Smith (Imperial College London) is leading on developing a methods framework for assessing the cost-effectiveness of different delivery platforms (e.g. primary vs. secondary care) in the context of Universal Health Coverage. Related Publications and reports so far include:

Using the RC for transmission models, and presenting disaggregated social perspectives

Professor Anna Vassall and colleagues at LSHTM are leading an exploration of presenting the disaggregated social perspectives when conducting economic evaluations of multi-sectoral interventions, and the application of the iDSI RC to transmission model based economic evaluation.

  • Identifying key challenges and solutions in applying the iDSI Reference Case to economic evaluations using transmission models with a particular focus on principles 11 (equity) and 8 (heterogeneity)
  • Developing methods for reporting and analysing the “disaggregated societal perspective” in the Reference Case (principle no. 7)

Related initiatives

The initial research that led to the development of the IDSI Reference Case found wide variation in methodological quality in economic evaluations conducted in LMIC settings.
The Reference Case consolidated this research and created central principles for economic evaluation, but further methodological research is needed to ensure economic evaluation is a useful tool for good decision making in health in LMICs.
iDSI welcomes further initiatives related to methodological research and utilisation of analysis.