 The blind or blinded experiment is an experiment in which information about the test is masked kept from the participant, to reduce or eliminate bias, until after a trial outcome is known. It is understood that bias may be intentional or subconscious, thus no dishonesty is implied by blinding. If both tester and subject are blinded, the trial is called a double blind experiment. Blind testing is used wherever items are to be compared without influences from tester's preferences or expectations. For example in clinical trials to evaluate the effectiveness of medicinal drugs and procedures without placebo effect, observer bias, or conscious deception, and comparative testing of commercial products to objectively assess user preferences, without being influenced by branding and other properties not being tested. Blinding can be imposed on researchers, technicians, or subjects. The opposite of a blind trial is an open trial. Blind experiments are an important tool of the scientific method, in many fields of research medicine, psychology and the social sciences. Social sciences such as physics and biology, applied sciences such as market research, and many others. In some disciplines, such as medicinal drug testing, blind experiments are considered essential. In some cases, while blind experiments would be useful, they are impractical or unethical, an example is in the field of developmental psychology, although it would be informative to raise children under arbitrary experimental conditions, such as on the remote island with a fabricated inculturation, it is a violation of ethics and human rights. The terms blind adjective or too blind transitive verb when used in this sense are figurative extensions of the literal idea of blind folding someone. The terms masked or too masked may be used for the same concept, this is commonly the case in oft-almology, where the word blind is often used in the littoral sense. Some who question mark original research, argue that the use of the term blind for academic review or experiments is offensive and prefer the alternative term masked or anonymous.