This study discusses the value of primary data collection as part of health technology assessment (HTA). Primary data collection can help reduce uncertainty in HTA and better inform evidence-based decision making. However, methodological issues such as choosing appropriate study design and practical concerns such as the value of collecting additional information need to be addressed. The authors emphasize the conditions required for successful primary data collection in HTA: experienced researchers, sufficient funding, and coordination among stakeholders, government, and researchers. The authors conclude that, under specific conditions, primary data collection is a worthwhile endeavor in the HTA process.