Experimental Carryover Effect
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An Experimental Carryover Effect is an order effect that is an effect or factor of an experiment that alter the outcome of a subsequent experiment.
- Example(s):
- Counter-Example(s):
- See: Within-Subjects research design. Washout Period, Treatment Period, Crossover Clinical Trial, Clinical Trial Eligibility Criterion, Concomitant Medication.
References
2018
- (Bjorndal, 2018) ⇒ Ludvig Daae Bjorndal (2018). "Carryover effects: What are they, why are they problematic, and what can you do about them?". In: Cochrane.
- QUOTE: Carryover effects are challenging for within-subjects research designs, that is, when the same participants are exposed to all experimental treatments and results are compared across different treatments. These designs are useful, among other reasons, because they allow a near perfect match of subject characteristics as the researcher compares measurements of the same participant. However, as the same subjects are used in all experimental treatments, there is a possibility that a previous treatment can alter behaviour in a subsequent experimental treatment. This is known as a carryover effect.
2017
- (Price et al., 2017) ⇒ Paul C. Price, Rajiv Jhangiani, I-Chant A. Chiang, Dana C. Leighton, and Carrie Cuttler (2022)"5.2 Experimental Design". In: [Research Methods in Psychology 3rd American Edition. PB Press Books]
- QUOTE: The primary disadvantage of within-subjects designs is that they can result in order effects. An order effect occurs when participants’ responses in the various conditions are affected by the order of conditions to which they were exposed. One type of order effect is a carryover effect. A carryover effect is an effect of being tested in one condition on participants’ behavior in later conditions. One type of carryover effect is a practice effect, where participants perform a task better in later conditions because they have had a chance to practice it. Another type is a fatigue effect, where participants perform a task worse in later conditions because they become tired or bored. Being tested in one condition can also change how participants perceive stimuli or interpret their task in later conditions. This type of effect is called a context effect (or contrast effect). For example, an average-looking defendant might be judged more harshly when participants have just judged an attractive defendant than when they have just judged an unattractive defendant. Within-subjects experiments also make it easier for participants to guess the hypothesis. For example, a participant who is asked to judge the guilt of an attractive defendant and then is asked to judge the guilt of an unattractive defendant is likely to guess that the hypothesis is that defendant attractiveness affects judgments of guilt.
2014
- (O'Connor et al., 2014) ⇒ Constance M. O'Connor, D. Ryan Norris, Glenn T. Crossin, Steven J. Cooke (2014). "Biological carryover effects: linking common concepts and mechanisms in ecology and evolution". In: Ecosphere, 5(3), 1-11.
- QUOTE: The concept of carryover effects was first recognized in repeated measures clinical trials, where certain factors could ‘carry over' from one treatment to another in laboratory studies (...)
2011
- (Evans, 2011) ⇒ Scott R. Evans (2011). "Clinical Trial Structures". In: Journal of Experimental Stroke & Translational Medicine, 3(1):8-18.
- QUOTE: The primary concern with crossover trials is the potential “carry-over effect”. If the residual effect of the treatment provided in the first period continues into the second period when assessments of the second treatment are made (despite the discontinuation of the treatment at the end of the first period), then treatment comparisons could be biased since one cannot distinguish between the treatment effect and the carry-over effect. For this reason, a “washout” period is often built into the study design to separate two treatment periods to eliminate “carry-over” effects. A frequent recommendation is for the washout period to be at least 5 times the half-life of the treatment with the maximum half-life in the study. Endpoint evaluations can also be made at the end of a period to allow more time for the effects of prior treatments to dissipate.