An opportunity cost approach to sample size calculation in cost-effectiveness analysis

Area of Science:

• Health Economics
• Clinical Trial Design
• Biostatistics

Background:

• Economic evaluations in clinical trials necessitate adequate sample sizes.
• Incremental cost-effectiveness ratio (ICER) and threshold (lambda) are common efficiency metrics.
• ICER-based sample size calculations may conflict with economic opportunity cost principles.

Purpose of the Study:

• To develop and illustrate an opportunity cost approach for sample size calculations in economic evaluations alongside clinical trials.
• To compare the opportunity cost method with the ICER threshold method for sample size requirements.
• To address concerns regarding the validity of ICER-based sample size calculations.

Main Methods:

• Development of an opportunity cost framework for sample size determination.
• Illustration of the proposed method with a numerical example.
• Comparative analysis of sample size requirements between the opportunity cost and ICER threshold methods.

Main Results:

• The opportunity cost approach provides an alternative to ICER-based sample size calculations.
• Both methods may result in larger sample size requirements depending on the scenario.
• The opportunity cost method requires additional data but aligns with economic theory.

Conclusions:

• The opportunity cost approach offers a conceptually sound method for sample size calculation in economic evaluations.
• While requiring more data, this approach enhances the validity of efficiency analyses.
• Decision-makers benefit from analyses consistent with opportunity cost principles.