Glossary of Technology Assessment Terms

Bias or systematic error is the deviation of results or inferences from the truth, or processes leading to such deviation. See also Referral Bias, or Selection Bias.

Healthcare technology is defined as prevention and rehabilitation, vaccines, pharmaceuticals, and devices, medical and surgical procedures, and the systems within which health is protected and maintained.

Technology assessment in health care is a multidisciplinary field of policy analysis. It studies the medical, social, ethical, and economic implications of development, diffusion, and use of health technology.

Clinical Guidelines are systematically developed statements for practitioners and patients about appropriate health care for specific clinical circumstances.

Database (or register) is any of a wide variety of repositories (often computerized) for observations and related information about a group of patients (e.g., adult males living in Göteborg) or a disease (e.g., hypertension) or an intervention (e.g., antihypertensive drug therapy) or other events or characteristics. Depending upon criteria for inclusion in the database, the observations may have controls. Although these can be useful, a variety of confounding factors (e.g., no randomization and possible selection bias in the process by which patients or events are recorded) make them relatively weak methods for determining causal relationships between an intervention and an outcome.

Decision Analysis is a technique used under conditions of uncertainty for systematically representing and examining all the relevant information for a decision and the uncertainty around that information. The available choices are plotted on a decision tree. At each branch, or decision node, the probabilities of each outcome that can be predicted are estimated. The relative worth or preferences of decision-makers for the various possible outcomes for a decision can also be estimated and incorporated into a decision analysis.

Effectiveness is the extent to which a specific intervention, when used under ordinary circumstances, does what it is intended to do. Clinical trials that assess effectiveness are sometimes called management trials.

Efficacy The extent to which an intervention produces a beneficial result under ideal conditions. Clinical trials that assess efficacy are sometimes called explanatory trials and are restricted to participants who fully co-operate.

Evidence-based Health Care extends the application of the principles of Evidence- Based Medicine (see below) to all professions associated with health care, including purchasing and management.

Evidence-based Decision-making in a health policy context is the application of the best available scientific evidence to policy decisions about specific medical treatments or changes in the delivery system. The goals of evidence-based decision making are to improve the quality of care, increase the efficiency of care delivery, and improve the allocation of health care resources.

Gold standard is a method, procedure, or measurement that is widely accepted as being the best available.

Meta-analysis is the use of statistical techniques in a systematic review to integrate the results of included studies. Sometimes used as a synonym for systematic reviews, where the review includes meta-analysis.

Randomized Controlled Trial is an experiment in which investigators randomly allocate eligible people into intervention groups to receive or not to receive one or more interventions that are being compared. The results are assessed by comparing outcomes in the treatment and control groups. NOTE: when using randomised controlled trial as a search term (publication type) in MEDLINE, the US spelling (randomized) must be used.

Referral Bias is the sequence of referrals that may lead patients from primary to tertiary centres raises the proportion of more severe or unusual cases, thus increasing the likelihood of adverse or unfavorable outcomes.

Registries ( see database)

Risk Factors are patient characteristics or factors associated with an increased probability of developing a condition or disease in the first place.

Selection Bias is a bias in assignment or a confounding variable that arises from study design rather than by chance. These can occur when the study and control groups are chosen so that they differ from each other by one or more factors that may affect the outcome of the study.

Systematic Review is a review of a clearly formulated question that uses systematic and explicit methods to identify, select and critically appraise relevant research, and to collect and analyse data from the studies that are included in the review. Statistical methods (meta-analysis) may or may not be used to analyze and summarize the results of the included studies.