E. Basic HTA Frameworks
There is great variation in the scope, selection of methods and level of detail in the practice of HTA. Nevertheless, most HTA activity involves some form of the following basic steps.
Identify assessment topics
Specify the assessment problem or questions
Determine organizational locus or responsibility for assessment
Retrieve available relevant evidence
Generate or collect new evidence (as appropriate)
Appraise/interpret quality of the evidence
Integrate/synthesize evidence
Formulate findings and recommendations
Disseminate findings and recommendations
Monitor impact
Not all assessment programs conduct all of these steps, and they are not necessarily conducted in a linear manner. Many HTA programs rely largely on integrative methods of reviewing and synthesizing data (using systematic reviews and meta-analyses) based on existing relevant primary data studies (reported in journal articles or from epidemiological or administrative data sets). Some assessment efforts involve multiple cycles of retrieving/collecting, interpreting, and integrating evidence before completing an assessment. The steps of appraising and integrating evidence may be done iteratively, such as when individual primary data studies pertaining to a particular evidence question are appraised individually for quality and then are integrated into a body of evidence, which in turn is appraised for its overall quality, as described in chapter III and chapter IV. Depending on the circumstances of an HTA, the dissemination of findings and recommendations and monitoring of impact may not be parts of the HTA itself, although they may be important responsibilities of the sponsoring program or parent organization. As indicated by various chapter and section headings, all ten of the basic steps of HTA listed above are described in this document.
EUnetHTA has developed a “core model” for HTA to serve as a generic framework to enable international collaboration for producing and sharing the results of HTAs (EUnetHTA 2013). Core HTAs are intended to serve as a basis for local (i.e., a particular nation, region, or program) reports, and as such do not contain recommendations on technology use. The core model involves the following domains and production phases (EUnetHTA 2008; Lampe 2009):
EUnetHTA Core Model Domains
Health problem and current use of technology
Description and technical characteristics of technology
Safety
Clinical effectiveness
Costs and economic evaluation
Ethical analysis
Organizational aspects
Social aspects
Legal aspects
EUnetHTA Core Model Phases
Definition of the technology to be assessed
Definition of project type
Relevance of assessment elements
Translation of relevant issues into research questions
Compiling of a core HTA protocol
Research
Entering the results
HTA embraces a diverse group of methods. Two of the main types of HTA methods are primary data collection methods and secondary or integrative methods. Primary data methods (described in chapter III) involve collection of original data, such as clinical trials and observational studies. Integrative methods, or secondary or synthesis methods (chapter IV), involve combining data or information from existing sources, including from primary data studies. (Economic analysis methods, chapter V) can involve one or both of primary data methods and integrative methods.
Most HTA programs use integrative approaches, with particular attention to formulating findings that are based on distinguishing between stronger and weaker evidence drawn from available primary data studies. Some HTA programs do collect primary data, or are part of larger organizations that collect primary data. It is not always possible to conduct, or base an assessment on, the most rigorous types of studies. Indeed, policies often must be made in the absence, or before completion, of definitive studies. Given their varying assessment orientations, resource constraints and other factors, HTA programs tend to rely on different combinations of methods. Even so, the general trend in HTA is to call for and emphasize evidence based on the more rigorous and systematic methods.