blind procedures and bias — VCE psychology, live

Blind procedures and bias

People who expect to improve tend to improve, and people who expect a result tend to find it. A placebo gives the control group the same expectation as the treatment group, so participant expectancy appears in both groups and cancels out of the difference. Single-blind keeps participants from knowing which they received; double-blind also keeps the experimenter who interacts with and scores them from knowing, so experimenter effects such as generous rating and subtle cues have nowhere to go. Blinding never deletes the placebo effect: it matches it, and only the true difference is left. This is the real knowscape from knowhere, not a picture of one. Drag it. Watch what actually changes.

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why this one carries the topic.

A treatment bar and a placebo bar stacked from natural recovery, true effect, participant expectancy and experimenter inflation. Toggles for who knows the allocation name the procedure (open, single-blind, double-blind) and move the measured gap away from or back to the true gap.

what examiners catch — Students write that double-blind removes the placebo effect, or that blinding hides the hypothesis.

five things, not forty.

A placebo is an inactive treatment given to the control group so that expecting to improve happens in both groups and cancels out of the measured difference.

Single-blind: participants do not know whether they received the treatment or the placebo, which controls participant expectancy (the placebo effect in the gap).

Double-blind: the experimenter who allocates, interacts with or scores participants also does not know, which controls experimenter effects such as generous rating or cues.

Blinding does not remove the placebo effect; the placebo group still improves, and the point is that the effect becomes equal in both groups.

The experimenter always knows the hypothesis; double-blind works because they cannot tell which score the hypothesis wants to be higher.

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knowhere maps every concept to what it rests on and what rests on it — 3 underneath this one, 0 built on top. Each one says why, in a sentence, not as an arrow on a diagram.

this conceptblind procedures and biasA treatment bar and a placebo bar stacked from natural recovery, true effect, participant expectancy and experimenter inflation.

sits under itexperimental method and variablesbecause Needs a control group, an IV and a DV to see what blinding protects.

sits under itvalidity and reliabilitybecause Bias is a threat to validity, not a random error.

sits under itsampling and allocationbecause Allocation is the thing the blind hides.

9 more, same treatment.

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validity and reliabilitylive →ethics: concepts and guidelinesin the appexperimental method and variablesin the appsampling techniquesin the appvariables: the four that matterin the appstatistics and significancein the appaccuracy, precision and validityin the appsampling and allocationin the appchoosing an investigation methodologyin the app

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