4. Clinical effectiveness assessment in HTA

The last challenge is to understand how we might perceive and value the differences between outcomes. If a medicine prolongs life by 0.2 years, we still need to know:

• how much a patient would value 0.2 years of additional life expectancy
• if all patients experience roughly the same gains or if there are dramatic differences between patients, and
• if all patients value these gains similarly.

A new medicine that increased life expectancy by an average of 0.2 years would be perceived differently if it worked in some patients but had no effect on others, when compared with a scenario where all patients gained 0.2 years with little differences across patients.

There are several mechanisms that can be used to understand the relative value that patients and providers put on differences in health outcomes. One is qualitative research, such as surveys or focus groups, intended to provide an understanding of which outcomes are most important to patients (you will learn more about qualitative research in Course 4). Another is quantitative research based on scales, which can assign numerical values to specific outcomes in different states of health. In both cases, a proper and thorough validation of the measurement instruments should be performed.