Objectives: Health Technology Assessment (HTA) as a method for producing evidence in the health-care sector has been used for more than 25 years but has grown in extent during the past years. The objective of this study is to explore a possible evolution in these HTAs, in type of assessed technologies, in type of assessors, and in its methods.

Methods: A structured literature review was conducted of 433 HTA reports from the period 1989 to 2002 by eleven leading HTA institutions worldwide. The review focused on the methodology used, the assessors, and the assessed technologies and was designed to elucidate general time-trends in the practical application of HTA.

Results: The study shows that literature reviews are still the most often used method of assessment and accounts for a relatively stable fraction of assessments. The fraction of economic evaluations shows a slightly decreasing trend in contrast to randomized controlled trials and modeling/evaluations, which are applied more frequently. The data also demonstrate a more frequent use of external partners as assessors and a shift between devices and pharmaceuticals as assessed technologies.

Conclusions: The study shows an increase in the number of HTAs but no major developments in assessment methods used and, therefore, no widespread spillover from the development in research methods in general to the field of HTA methodology.