TA uses an interdisciplinary approach in its systematic and comprehensive analysis of the possible consequences of the use of particular technologies (not necessarily "new" ones). On the basis of the information gained in this way options can be devised for those involved in policy-making and the control of technology. Particular attention is paid to the analysis of unintended and generally long-term secondary or tertiary effects.
Because of the nature of the object of research and the interdisciplinary composition of the research team, a variety of quantitative and qualitative methods are used: brainstorming, literature research, document analysis, expert consultation, case studies, scenario development, and also certain processes calling for public involvement. The methods must be adapted to the subject under investigation.
The ideal-typical routine of a TA study is as follows:
- problem definition
- description of the technology
- prediction of future technology development
- description of society and persons affected
- prediction of social developments
- identification, analysis and evaluation of consequence
- analysis of political options
- communication of the results in a generally accessible form
A distinction can be made between project-induced, technology-induced and problem-induced technology assessment studies.
Project-induced TA studies are investigations into the possible consequences of a specific project (e.g. power stations, highway engineering, etc.). Where the focus is on environmental aspects, these studies are also known as "environmental compatibility studies" (ECS). In these cases a study focusing on one important aspect is preferred to the global TA approach.
Technology-induced TA studies are concerned with the impact of a specific technology on society and the natural environment. Examples here include specific information technology or genetic engineering applications.
In the problem-induced approach the main focus is on identifying the different possible solutions to an existing or future social problem. Possible political responses can be suggested through a comparative assessment of alternative technological development routes. Examples here include TA studies into traffic, energy supply and use, or waste problems.
The scope and depth of analysis in TA studies can vary considerably. Macro-assessments (comprehensive assessments) are in keeping with the global TA approach and require 10 to 15 person-years to complete. Mini-assessments are scaled down to one to three person-months and are used to analyse a limited problem in detail or a broad problem in general terms. Less detailed micro-assessments can provide policy-makers with information at short notice and tend to be in the form of a literature analysis and extended brainstorming. They take around three man-months.