Worldwide, billions of dollars are invested in medical product development and there is an increasing pressure to maximize the revenues of these investments. That is, governments need to be informed about the benefits of spending public resources, companies need more information to manage their product development portfolios and even universities may need to direct their research programmes in order to maximize societal benefits. Assuming that all medical products need to be adopted by the heavily regulated healthcare market at one point in time, it is worthwhile to look at the logic behind healthcare decision making, specifically, decisions on the coverage of medical products and decisions on the use of these products under competing and uncertain conditions. With the growing tension between leveraging economic growth through R&D spending on the one hand and stricter control of healthcare budgets on the other, several attempts have been made to apply the health technology assessment (HTA) methodology to earlier stages of technology development and implementation. For instance, horizon scanning was introduced to systematically assess emerging technologies in order to inform health policy. Others have introduced iterative economic evaluation, e.g. economic evaluations in earlier stages of clinical research. However, most of these methods are primarily intended to support governments in making decisions regarding potentially expensive new medical products. They do not really inform biomedical product developers on the probability of return on investment, nor do they inform about the market needs and specific requirements of technologies in development. It is precisely this aspect that increasingly receives attention, i.e. is it possible to use HTA tools and methods to inform biomedical product development and to anticipate further development and market access. Several methods have been used in previous decades, but have never been compiled in a comprehensive review. The main objective of this article was to provide an overview of previous work and methods in the field of early HTA, and to put these approaches in perspective through a conceptual framework introduced in this paper. A particular goal of the review was to familiarize decision makers with available techniques that can be employed in early-stage decision making, and to identify opportunities for further methodological growth in this emerging field of HTA.