NASA Categories of Evidence comprise a matrix or scale denoting the sources of evidence provided in the

Human Research Program The Human Research Program (HRP) was created in October 2005 at Johnson Space Center (JSC) in response to NASA's desire to move human research project management away from headquarters to the JSC. The HRP is an applied research and technology p ...

's various

evidence Evidence for a proposition is what supports this proposition. It is usually understood as an indication that the supported proposition is true. What role evidence plays and how it is conceived varies from field to field. In epistemology, evidenc ...

reports, and thus potentially their

probative Relevance, in the common law of evidence, is the tendency of a given item of evidence to prove or disprove one of the legal elements of the case, or to have probative value to make one of the elements of the case likelier or not. Probative is a te ...

value and

efficacy Efficacy is the ability to perform a task to a satisfactory or expected degree. The word comes from the same roots as ''effectiveness'', and it has often been used synonymously, although in pharmacology a pragmatic clinical trial#Efficacy versu ...

.NASA Categories of Evidence
/ref> Authors in the Program were urged to label their evidence according to whether it was based on

controlled experiment A scientific control is an experiment or observation designed to minimize the effects of variables other than the independent variable (i.e. confounding variables). This increases the reliability of the results, often through a comparison betw ...

observation Observation is the active acquisition of information from a primary source. In living beings, observation employs the senses. In science, observation can also involve the perception and recording of data via the use of scientific instruments. The ...

, or

expert opinion An expert witness, particularly in common law countries such as the United Kingdom, Australia, and the United States, is a person whose opinion by virtue of education, training, certification, skills or experience, is accepted by the judge as ...

References

Human spaceflight NASA {{NASA-stub