Assertion: controlled experimentation | /r/HasProperty | difficult
Facets:
value: extremely
type: DEGREE
Source sentences:
text: Natural experiments are used when such controlled experimentation would be too difficult, expensive, or unethical as is the case with many human experiments.
text: Natural experiments are employed as study designs when controlled experimentation is extremely difficult to implement or unethical, such as in several research areas addressed by epidemiology (like evaluating the health impact of varying degrees of exposure to ionizing radiation in people living near Hiroshima at the time of the atomic blast) and economics (like estimating the economic return on amount of schooling in US adults).
text: Natural experiments are considered for study designs whenever controlled experimentation is difficult, such as in many problems in epidemiology and economics.