double-blind study

• 二重盲検比較試験、二重盲検試験、二重盲検法

関

double-blind method、double-blind trial

WordNet

1. used of flowers having more than the usual number of petals in crowded or overlapping arrangements; "double chrysanthemums have many rows of petals and are usually spherical or hemispherical"
2. increase twofold; "The population doubled within 50 years" (同)duplicate
3. a base hit on which the batter stops safely at second base; "he hit a double to deep centerfield" (同)two-base hit, two-bagger, two-baser
4. someone who closely resembles a famous person (especially an actor); "he could be Gingrichs double"; "shes the very image of her mother" (同)image, look-alike
5. a stand-in for movie stars to perform dangerous stunts; "his first job in Hollywood was as a double for Clark Gable" (同)stunt man, stunt woman
6. a quantity that is twice as great as another; "36 is the double of 18"
7. twice as great or many; "ate a double portion"; "the dose is doubled"; "a twofold increase" (同)doubled, twofold, two-fold
8. consisting of or involving two parts or components usually in pairs; "an egg with a double yolk"; "a double (binary) star"; "double doors"; "dual controls for pilot and copilot"; "duple (or double) time consists of two (or a multiple of two) beats to a measure" (同)dual, duple
9. having more than one decidedly dissimilar aspects or qualities; "a double (or dual) role for an actor"; "the office of a clergyman is twofold; public preaching and private influence"- R.W.Emerson; "every episode has its double and treble meaning"-Frederick Harrison (同)dual, twofold, two-fold, treble, threefold, three-fold
10. having two meanings with intent to deceive; "a sly double meaning"; "spoke with forked tongue" (同)forked
11. bridge: make a demand for (a card or suit)
12. do double duty; serve two purposes or have two functions; "She doubles as his wife and secretary"
13. downward and forward; "he was bent double with pain"
14. hit a two-base hit
15. large enough for two; "a double bed"; "a double room"
16. two together; "some people sleep better double"
17. be a student; follow a course of study; be enrolled at an institute of learning
18. a room used for reading and writing and studying; "he knocked lightly on the closed door of the study"
19. applying the mind to learning and understanding a subject (especially by reading); "mastering a second language requires a lot of work"; "no schools offer graduate study in interior design" (同)work
20. a composition intended to develop one aspect of the performers technique; "a study in spiccato bowing"
21. a state of deep mental absorption; "she is in a deep study"
22. someone who memorizes quickly and easily (as the lines for a part in a play); "he is a quick study"
23. give careful consideration to; "consider the possibility of moving" (同)consider
24. learn by reading books; "He is studying geology in his room"; "I have an exam next week; I must hit the books now" (同)hit the books
25. think intently and at length, as for spiritual purposes; "He is meditating in his study" (同)meditate, contemplate
26. make dim by comparison or conceal (同)dim
27. unable or unwilling to perceive or understand; "blind to a lovers faults"; "blind to the consequences of their actions"
28. a protective covering that keeps things out or hinders sight; "they had just moved in and had not put up blinds yet" (同)screen
29. a hiding place sometimes used by hunters (especially duck hunters); "he waited impatiently in the blind"
30. people who have severe visual impairments, considered as a group; "he spent hours reading to the blind"
31. not based on reason or evidence; "blind hatred"; "blind faith"; "unreasoning panic" (同)unreasoning
32. unable to see; "a person is blind to the extent that he must devise alternative techniques to do efficiently those things he would do with sight if he had normal vision"--Kenneth Jernigan (同)unsighted
33. make blind by putting the eyes out; "The criminals were punished and blinded"
34. render unable to see
35. provide with or construct with studs; "stud the wall"
36. ornament consisting of a circular rounded protuberance (as on a vault or shield or belt) (同)rivet
37. poker in which each player receives hole cards and the remainder are dealt face up; bets are placed after each card is dealt (同)stud poker
38. adult male horse kept for breeding (同)studhorse
39. a man who is virile and sexually active (同)he-man, macho-man
40. increase by a factor of two; "doubling with a computer took no time at all"
41. raising the stakes in a card game by a factor of 2; "I decided his double was a bluff" (同)double

PrepTutorEJDIC

1. (数量・強さ・重さ・価値などが)『2倍の』,倍の / 『二重の』,二様の;複の,対の,2人用の / 表裏のある,二心ある / (意味が)二様にとれる,あいまいな / (花が)八重の,重弁の / 『2倍に』,2倍だけ(twice) / 二重に,二様に / 対をなして,二人いっしょに / 〈U〉『2倍』[の数量・価額など] / 〈C〉2倍のもの / 〈C〉よく似た人(物),生き写し / 〈C〉(映画の)代役 / 《複数形》《単数扱い》(テニスなどの)ダブルス / 〈C〉(獲物が追っ手を逃れるときなどの)逆走,急転回 / 〈C〉2塁打 / 〈C〉(ブリッジの点の)倍加 / 〈C〉(競馬・ドッグレースの)重勝式のかけ,複式 / …‘を'『2倍にする』 / …‘を'『二つ折りにする』 / …‘の'2倍の数(量)がある / 〈二役〉‘を'ひとりで演ずる / 〈船が〉〈岬〉‘を'回る / 『2倍になる』 / (…の役を)兼ねる《+『as』+『名』》 / (急に)取って返す,逆戻りする《+『back』》 / 二つ折りになる / (ブリッジで)相手のせり高を倍加する / 2塁打を打つ
2. 〈U〉(一般に)『勉強』,学習すること / 〈C〉(…の)勉強,研究《+of+名》 / 〈C〉〈U〉(…の)『綿密な調査』,検討《+of+名》 / 〈C〉研究対象(問題,事項);学科 / 〈C〉『書斎』,勉強部屋 / 〈C〉(美術・文学などの)習作,試作,スケッチ,(音楽の)練習曲,エチュード / …‘を'『勉強する』,学ぶ,研究する / …‘を'『よく注意して見る』,しげしげと見る / …‘を'『調査する』,検討する / …‘を'考慮する,配慮する / 〈せりふなど〉‘を'覚えようとする / 『勉強する』,学ぶ,研究する
3. 『目の見えない』,盲目の(sightless) / 《補語にのみ用いて》(…を)見る目がない,気がついていない《+『to』+『名』》 / 盲目的な,めくらめっぽうの(reckless) / (特に車の運転者に)隠れて見えない / (通りなどが)行き止まりの,出口のない;(建築物が)窓のない / 肉眼で見えないでする,計器だけに頼る / 〈人〉‘の'目をくらませる,'を'盲目にする / (…に対して)〈人〉‘の'判断力(分別)を失わせる《+『名』〈人〉+『to』+『名』》 / 『日よけ』,すだれ,よろい戸,ブラインド / 人の目をごまかすもの,見せかけ / 《米》(猟師の)隠れ場 / 目が見えなくて
4. 《おもに米》種馬 / 《集合的に》(一群の)繁殖用動物(種馬,種牛など)
5. (インテリアなどに用いる)飾りびょう / カフスボタン,カラーボタン / (建物の)間柱 / (…を)…‘に'ちりばめる《+名+with+名》 / …‘に'点在(散在)している / …‘に'間柱をつける

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2016/04/18 06:16:38」(JST)

wiki en

[Wiki en表示]

A 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 unconscious, 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 testers' preferences or expectations, for example in clinical trials to evaluate the effectiveness of medicinal drugs and procedures without placebo effect, nocebo 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, subjects, and funders. 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, natural 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 a remote island with a fabricated enculturation, it is a violation of ethics and human rights.

The terms blind (adjective) or to blind (transitive verb) when used in this sense are figurative extensions of the literal idea of blindfolding someone. The terms masked or to mask may be used for the same concept; this is commonly the case in ophthalmology, where the word 'blind' is often used in the literal sense.

History

The French Academy of Sciences originated the first recorded blind experiments in 1784: the Academy set up a commission to investigate the claims of animal magnetism proposed by Franz Mesmer. Headed by Benjamin Franklin and Antoine Lavoisier, the commission carried out experiments asking mesmerists to identify objects that had previously been filled with "vital fluid", including trees and flasks of water. The subjects were unable to do so. The commission went on to examine claims involving the curing of "mesmerized" patients. These patients showed signs of improved health, but the commission attributed this to the fact that these patients believed they would get better—the first scientific suggestion of the now well-known placebo effect.

In 1799 the British chemist Humphry Davy performed another early blind experiment. In studying the effects of nitrous oxide (laughing gas) on human physiology, Davy deliberately did not tell his subjects what concentration of the gas they were breathing, or whether they were breathing ordinary air.

Blind experiments went on to be used outside of purely scientific settings. In 1817, a committee of scientists and musicians compared a Stradivarius violin to one with a guitar-like design made by the naval engineer François Chanot. A well-known violinist played each instrument while the committee listened in the next room to avoid prejudice.

One of the first essays advocating a blinded approach to experiments in general came from Claude Bernard in the latter half of the 19th century, who recommended splitting any scientific experiment between the theorist who conceives the experiment and a naive (and preferably uneducated) observer who registers the results without foreknowledge of the theory or hypothesis being tested. This suggestion contrasted starkly with the prevalent Enlightenment-era attitude that scientific observation can only be objectively valid when undertaken by a well-educated, informed scientist.

Double-blind methods came into especial prominence in the mid-20th century.

Single-blind trials

Single-blind describes experiments where information that could introduce bias or otherwise skew the result is withheld from the participants, but the experimenter will be in full possession of the facts.

In a single-blind experiment, the individual subjects do not know whether they are so-called "test" subjects or members of an "experimental control" group. Single-blind experimental design is used where the experimenters either must know the full facts (for example, when comparing sham to real surgery) and so the experimenters cannot themselves be blind, or where the experimenters will not introduce further bias and so the experimenters need not be blind. However, there is a risk that subjects are influenced by interaction with the researchers – known as the experimenter's bias. Single-blind trials are especially risky in psychology and social science research, where the experimenter has an expectation of what the outcome should be, and may consciously or subconsciously influence the behavior of the subject.

A classic example of a single-blind test is the Pepsi Challenge. A tester, often a marketing person, prepares two sets of cups of cola labeled "A" and "B". One set of cups is filled with Pepsi, while the other is filled with Coca-Cola. The tester knows which soda is in which cup but is not supposed to reveal that information to the subjects. Volunteer subjects are encouraged to try the two cups of soda and polled for which ones they prefer. One of the problems with a single-blind test like this is that the tester can unintentionally give subconscious cues which influence the subjects. In addition, it is possible the tester could intentionally introduce bias by preparing the separate sodas differently (e.g., by putting more ice in one cup or by pushing one cup closer to the subject). If the tester is a marketing person employed by the company which is producing the challenge, there's always the possibility of a conflict of interest where the marketing person is aware that future income will be based on the results of the test.

Double-blind trials

"Double blind" redirects here. It is not to be confused with double bind.

Double-blind describes an especially stringent way of conducting an experiment which attempts to eliminate subjective, unrecognized biases carried by an experiment's subjects (usually human) and conductors. Double-blind studies were first used in 1907 by W. H. R. Rivers and H. N. Webber in the investigation of the effects of caffeine.

In most cases, double-blind experiments are regarded to achieve a higher standard of scientific rigor than single-blind or non-blind experiments.

In these double-blind experiments, neither the participants nor the researchers know which participants belong to the control group, nor the test group. Only after all data have been recorded (and, in some cases, analyzed) do the researchers learn which participants were which. Performing an experiment in double-blind fashion can greatly lessen the power of preconceived notions or physical cues (e.g., the placebo effect, observer bias, experimenter's bias) to distort the results (by making researchers or participants behave differently from in everyday life). Random assignment of test subjects to the experimental and control groups is a critical part of any double-blind research design. The key that identifies the subjects and which group they belonged to is kept by a third party, and is not revealed to the researchers until the study is over.

Double-blind methods can be applied to any experimental situation in which there is a possibility that the results will be affected by conscious or unconscious bias on the part of researchers, participants, or both. For example, in animal studies, both the carer of the animals and the assessor of the results have to be blinded; otherwise the carer might treat control subjects differently and alter the results.

Computer-controlled experiments are sometimes also erroneously referred to as double-blind experiments, since software may not cause the type of direct bias between researcher and subject. Development of surveys presented to subjects through computers shows that bias can easily be built into the process. Voting systems are also examples where bias can easily be constructed into an apparently simple machine based system. In analogy to the human researcher described above, the part of the software that provides interaction with the human is presented to the subject as the blinded researcher, while the part of the software that defines the key is the third party. An example is the ABX test, where the human subject has to identify an unknown stimulus X as being either A or B.

Triple-blind trials

A triple-blind study is an extension of the double-blind design; the committee monitoring response variables is not told the identity of the groups. The committee is simply given data for groups A and B. A triple-blind study has the theoretical advantage of allowing the monitoring committee to evaluate the response variable results more objectively. This assumes that appraisal of efficacy and harm, as well as requests for special analyses, may be biased if group identity is known. However, in a trial where the monitoring committee has an ethical responsibility to ensure participant safety, such a design may be counterproductive since in this case monitoring is often guided by the constellation of trends and their directions. In addition, by the time many monitoring committees receive data, often any emergency situation has long passed.

Use

In medicine

Double-blinding is relatively easy to achieve in drug studies, by formulating the investigational drug and the control (either a placebo or an established drug) to have identical appearance (color, taste, etc.). Patients are randomly assigned to the control or experimental group and given random numbers by a study coordinator, who also encodes the drugs with matching random numbers. Neither the patients nor the researchers monitoring the outcome know which patient is receiving which treatment, until the study is over and the random code is revealed.

Effective blinding can be difficult to achieve where the treatment is notably effective (indeed, studies have been suspended in cases where the tested drug combinations were so effective that it was deemed unethical to continue withholding the findings from the control group, and the general population), or where the treatment is very distinctive in taste or has unusual side-effects that allow the researcher and/or the subject to guess which group they were assigned to. It is also difficult to use the double blind method to compare surgical and non-surgical interventions (although sham surgery, involving a simple incision, might be ethically permitted). A good clinical protocol will foresee these potential problems to ensure blinding is as effective as possible. It has also been argued that even in a double-blind experiment, general attitudes of the experimenter such as skepticism or enthusiasm towards the tested procedure can be subconsciously transferred to the test subjects.

Evidence-based medicine practitioners prefer blinded randomised controlled trials (RCTs), where that is a possible experimental design. These are high on the hierarchy of evidence; only a meta analysis of several well designed RCTs is considered more reliable.

In physics

Modern nuclear physics and particle physics experiments often involve large numbers of data analysts working together to extract quantitative data from complex datasets. In particular, the analysts want to report accurate systematic error estimates for all of their measurements; this is difficult or impossible if one of the errors is observer bias. To remove this bias, the experimenters devise blind analysis techniques, where the experimental result is hidden from the analysts until they've agreed—based on properties of the data set other than the final value—that the analysis techniques are fixed.

One example of a blind analysis occurs in neutrino experiments, like the Sudbury Neutrino Observatory, where the experimenters wish to report the total number N of neutrinos seen. The experimenters have preexisting expectations about what this number should be, and these expectations must not be allowed to bias the analysis. Therefore, the experimenters are allowed to see an unknown fraction f of the dataset. They use these data to understand the backgrounds, signal-detection efficiencies, detector resolutions, etc.. However, since no one knows the "blinding fraction" f, no one has preexisting expectations about the meaningless neutrino count N' = N x f in the visible data; therefore, the analysis does not introduce any bias into the final number N which is reported. Another blinding scheme is used in B meson analyses in experiments like BaBar and CDF; here, the crucial experimental parameter is a correlation between certain particle energies and decay times—which require an extremely complex and painstaking analysis—and particle charge signs, which are fairly trivial to measure. Analysts are allowed to work with all the energy and decay data, but are forbidden from seeing the sign of the charge, and thus are unable to see the correlation (if any). At the end of the experiment, the correct charge signs are revealed; the analysis software is run once (with no subjective human intervention), and the resulting numbers are published. Searches for rare events, like electron neutrinos in MiniBooNE or proton decay in Super-Kamiokande, require a different class of blinding schemes.

The "hidden" part of the experiment—the fraction f for SNO, the charge-sign database for CDF—is usually called the "blindness box". At the end of the analysis period, one is allowed to "unblind the data" and "open the box".

In forensics

In a police photo lineup, an officer shows a group of photos to a witness or crime victim and asks him or her to pick out the suspect. This is basically a single-blind test of the witness's memory, and may be subject to subtle or overt influence by the officer. There is a growing movement in law enforcement to move to a double-blind procedure in which the officer who shows the photos to the witness does not know which photo is of the suspect.

In music

In recruiting musicians to perform in orchestras and so on, blind auditions are now routinely done: the musicians perform behind a screen so that their physical appearance and gender cannot prejudice the listener judging the performance.

References

External links

• "control group study" – The Skeptic’s Dictionary – More on why double blind is important.
• PharmaSchool JargonBuster Clinical Trial Terminology Dictionary

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Related Links

• double-blind study - definition of double-blind study by Medical ...

double-blind study, an experiment designed to test the effect of a treatment or substance by using groups of experimental and control subjects in which neither the subjects nor the investigators know which treatment or substance is ...

• double-blind study - definition of double-blind study by The ...

Thesaurus Antonyms Related Words Synonyms Legend: Noun 1. double-blind study - an experimental procedure in which neither the subjects of the experiment nor the persons administering the experiment know the critical aspects ...

Related Pictures

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★リンクテーブル★

リンク元	「二重盲検試験」「二重盲検比較試験」「double-blind method」「double-blind trial」
関連記事	「study」「blind」「blind study」「double」「stud」

「二重盲検試験」

　　[★]

英

double-blind study、double-blind trial

関

二重盲検法、二重盲検比較試験

「二重盲検比較試験」

　　[★]

英

double-blind study、double-blind trial

関

二重盲検試験、二重盲検法

「double-blind method」

　　[★]

• 二重盲検法、二重盲検

関

double-blind、double-blind study

「double-blind trial」

　　[★]

• 二重盲検比較試験、二重盲検試験

関

double-blind study

「study」

　　[★]

• n.

• 研究、勉学、学習
• (～の)研究、学問。[-ies](従事している)研究、学業(in,on,of,into)
• 慎重な調査、詳細な検討
• 研究対象/研究題目。研究論文、論考。[-ies]学科
• (～に関して)研究に値するもの、見もの、(～の)具体例(in)
• 書斎、勉強部屋、研究室

• vt.
• vi.

関

examine、exploration、explore、inquire、inquiry、investigate、investigation、investigational、investigative、laboratory research、probing、research、scan、surveillance、survey、work

　 　 　 　 　 　 　 　 　 　

「blind」

　　[★]

• adj.

• 盲目の、盲検法の

• n.

• 盲

関

blind method、blind study、blindness

　 　 　 　 　 　 　 　 　 　

「blind study」

　　[★]

• 盲検試験、盲検比較試験、盲検法

関

blind、blind method、blind trial

「double」

　　[★]

• adj.

同

outlet right ventricle

　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　 　

「stud」

　　[★]

• adj.

• 繁殖用の