Data collection methods in prospective economic evaluations: how accurate are the results?

Area of Science:

• Health Economics
• Pharmacoeconomics
• Research Methodology

Background:

• Economic evaluations often dichotomize studies into high internal validity (e.g., RCTs) versus high external validity (e.g., observational studies).
• This conventional view may oversimplify the complex interplay of factors affecting study validity.
• Intrastudy effects, particularly data collection strategies, are often overlooked.

Purpose of the Study:

• To challenge the traditional dichotomy of internal versus external validity in economic evaluations.
• To examine how intrastudy data collection strategies impact the validity of study findings.
• To propose a more nuanced understanding of validity as a continuum.

Main Methods:

• A comprehensive literature review was conducted to assess the impact of data collection strategies on internal validity.
• Two scenario models were developed to preliminarily understand the magnitude of the problem.
• Analysis focused on how different data collection methods influence resource and cost estimates.

Main Results:

• Data collection strategies demonstrably affect the internal validity of economic evaluations.
• Comparisons between prospective studies can be misleading due to variations in data collection methods.
• Combining different data collection methods can enhance and shift the overall validity of a study.

Conclusions:

• Validity in economic evaluations should be viewed as a continuum within a study, not a dichotomy.
• Proxies, patient self-reported data, and data collection methods significantly impact result validity.
• National guidelines for economic evaluations need to address data collection impacts, and evidence rankings should be adapted for pharmacoeconomics.