5 Demand Characteristics and the Concept of Quasi-Controls

Orne, Martin T.

doi:10.1093/acprof:oso/9780195385540.003.0005

Cited by 145 publications

(131 citation statements)

References 21 publications

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“…According to all theories about the mechanisms of placebo effect we are aware of, if the specific and non-specific effects in drug-treated subjects are associated, it is the specific effects that would influence the non-specific effect and the potential association can only be is positive: presence and increase in specific effect should increase the non-specific effects (see Kirsch (1985Kirsch ( , 1990; Orne (1969); Wickamasekera (1980); Ader and Cohen (1991)). While theories about placebo effects are concerned with the mechanisms of improvement due to non-specific aspects of the treatment, a major question in clinical practice is the efficacy of a drug and (in depression treatment), whether or not a patient who was treated and improved did so due to specific or non-specific effects, i.e.…”

Section: Discussionmentioning

confidence: 99%

Predicting Potential Placebo Effect in Drug Treated Subjects

Petkova¹,

Tarpey²,

Govindarajulu³

2009

The International Journal of Biostatistics

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Non-specific responses to treatment (commonly known as placebo response) are pervasive when treating mental illness. Subjects treated with an active drug may respond in part due to nonspecific aspects of the treatment, i.e, those not related to the chemical effect of the drug. To determine the extent a subject responds due to the chemical effect of a drug, one must disentangle the specific drug effect from the non-specific placebo effect. This paper presents a unique statistical model that allows for the separate prediction of a specific effect and non-specific effects in drug treated subjects. Data from a clinical trial comparing fluoxetine to a placebo for treating depression is used to illustrate this methodology.

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Section: Discussionmentioning

confidence: 99%

Predicting Potential Placebo Effect in Drug Treated Subjects

Petkova¹,

Tarpey²,

Govindarajulu³

2009

The International Journal of Biostatistics

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“…The difference in design is a consequence of having or not having a toll value to pivot around. The same 24 choice tasks were used for all respondents in order to minimise the likelihood that the design would influence the results (a phenomenon known as demand characteristics or demand induced effects; see Orne 1959Orne , 1969. The design is a D-optimal design (see Rose and Bliemer 2009) utilising priors obtained from a large pilot study involving over 250 respondents collected from another Australian capital city six months prior.…”

Section: Approachmentioning

confidence: 99%

Tollroads are only part of the overall trip: the error of our ways in past willingness to pay studies

Rose

Hensher

2013

Transportation

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With rare exception, actual tollroad traffic in many countries has failed to reproduce forecast traffic levels, regardless of whether the assessment is made after an initial year of operation or as long as ten years after opening. Pundits have offered many reasons for this divergence, including optimism bias, strategic misrepresentation, the promise to equity investors of early returns on investment, errors in land use forecasts, and specific assumptions underlying the traffic assignment models used to develop traffic forecasts. One such assumption is the selection of a behaviourally meaningful value of travel time savings (VTTS) for use in a generalised cost or generalised time user benefit expression that is the main behavioural feature of the traffic assignment (route choice) model. Numerous empirical studies using stated choice experiments have designed choice sets of alternatives as if users choose a tolled route or a free route under the (implied) assumption that the tolled route is tolled for the entire trip. Reality is often very different, with a high incidence of use of a non-tolled road leading into and connecting out of a tolled link. In this paper we recognise this feature of route choice and redesign the stated choice experiment to account for it. Furthermore, this study is a follow up to a previous study undertaken before a new toll road was in place, and it benefits from real exposure to the new toll road. We find that the VTTS is noticeably reduced, and if the VTTS is a significant contributing influence on errors on traffic forecasts, then the lower estimates make sense behaviourally.Key words: value of travel time savings, toll routes, free routes, choice experiment, errors in forecasts Acknowledgment. We thank the three referees for their comments as well as Stephane Hess who have provided invaluable comments which have resulted in numerous improvements to the paper.

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“…For example, one can ask a group of participants to respond in ways that confirm the study's hypotheses. Orne (1962Orne ( , 1969Orne ( /2009) also recommended the use of quasicontrols to evaluate the influence of demand characteristics. One such quasicontrol involves presenting the study to people from the same population as the "real" participants and to ask them to imagine that they are participants themselves but without incurring the actual treatment.…”

Section: What Should We Do About It? Practical Recommendationsmentioning

confidence: 99%

“…In the absence of deceptive procedures, only a small minority of report of studies refer to awareness checks. This is a matter of concern given that the impact of demand characteristics is in no way limited to situations in which the study participant is misguided as to the real purpose of the study (Orne, 1969(Orne, /2009.…”

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confidence: 99%

Low Hopes, High Expectations

Klein

Doyen

Leys

et al. 2012

Perspect Psychol Sci

104

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This article revisits two classical issues in experimental methodology: experimenter bias and demand characteristics. We report a content analysis of the method section of experiments reported in two psychology journals (Psychological Science and the Journal of Personality and Social Psychology), focusing on aspects of the procedure associated with these two phenomena, such as mention of the presence of the experimenter, suspicion probing, and handling of deception. We note that such information is very often absent, which prevents observers from gauging the extent to which such factors influence the results. We consider the reasons that may explain this omission, including the automatization of psychology experiments, the evolution of research topics, and, most important, a view of research participants as passive receptacles of stimuli. Using a situated social cognition perspective, we emphasize the importance of integrating the social context of experiments in the explanation of psychological phenomena. We illustrate this argument via a controversy on stereotype-based behavioral priming effects.

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5 Demand Characteristics and the Concept of Quasi-Controls

Cited by 145 publications

References 21 publications

Predicting Potential Placebo Effect in Drug Treated Subjects

Predicting Potential Placebo Effect in Drug Treated Subjects

Tollroads are only part of the overall trip: the error of our ways in past willingness to pay studies

Low Hopes, High Expectations

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