psyc 332 ch 9 rev Flashcards
Changes in the scores observed in one treatment condition that are caused by the lingering after effects of a specific earlier treatment condition
Carryover effects
In withinsubjects designs using a separate group of participants for every possible order of the treatment conditions With n different treatment conditions there are n factorial different orders
Complete counterbalancing
An example of a carryover effect in which the perception of a treatment condition is influenced by its contrast with the previous treatment
Contrast effect
In a withinsubjects design a procedure to minimize threats from order effects and timerelated factors by changing the order in which treatment conditions are administered from one participant to another so that the treatment conditions are matched with respect to time The goal is to use every possible order of treatments with an equal number of individuals participating in each sequence
Counter balancing
A threat to internal validity that occurs when prior participation in a treatment condition or measurement procedure tires the participants and influences their performance on subsequent measurements; an example of a testing effect or an order effect
Fatigue
A threat to internal validity from any outside event that influences the participants scores in one treatment differently than in another treatment
History
A threat to internal validity from changes in the measurement instrument that occur during the time a research study is being conducted Also known as instrumental bias or instrumental decay
Instrumentation
An n _ n matrix in which each of n different items appears exactly once in each column and exactly once in each row Used to identify sequences of treatment conditions for partial counterbalancing
Latin square
A research design comparing separate groups of individuals in which each individual in one group is matched with a participant in each of the other groups The matching is done so that the matched individuals are equivalent with respect to a variable that the researcher considers to be relevant to the study
Matched subjects design
A threat to internal validity from any physiological or psychological changes that occur in a participant during the time that research study is being conducted and that can influence the participants scores
Maturation
Whenever individuals participate in a series of treatment conditions and experience a series of measurements their behavior or performance at any point in the series may be influenced by experience that occurred earlier in the sequence Order effects include carryover effects and progressive error Also known as testing effects
Order effects
A system of counterbalancing that ensures that each treatment condition occurs first for one group of participants second for one group third for one group and so on but does not require that every possible order of treatment conditions be used
Partial counterbalancing
The loss of participants that occurs during the course of a research study conducted over time Attrition can be a threat to internal validity Also known as participant mortality
Participant attrition
A threat to internal validity that occurs when prior participation in a treatment condition or measurement procedure provides participants with additional skills that influence their performance on subsequent measurements An example of a testing effect or an order effect
Practice
In a research study changes in the scores observed in one treatment condition that are related to general experience in a research study over time but not to a specific treatment or treatments Common kinds of progressive error are practice effects and fatigue
Progressive error