Chapter 9 - Within Groups design Flashcards
What is a within subjects design?
- Single group of participants
* Tests/observes each individual in all the different treatments being compared
What is the other name of within subjects design?
Repeated Measures experimental design
What are the 2 possible structures for a within subjects design?
Sequential: Treatments administered one after the other
Concurrent: Treatments administered all at once
What are the 2 major sources of confounding in within subjects designs?
Enviromental variables and time-related variables
What are environmental variables?
Characteristics of the environment that may change from one treatment to another
What are time-related variables?
Factors influencing the participants between 1st and last measurements
What are the confounding variables related to history?
environmental events other than the treatment that change over time and may affect the scores in one treatment differently than in another treatment
EX: life at home, school, work between the treatments
What are the confounding variables related to maturation?
systematic changes in participants physiology/psychology that occur during a research study
What are the confounding variables related to instrumentation?
changes in a measuring instrument that occur over time (mostly with behavioural observation measures)
How is instrumentation also called?
instrumental bias or instrumental decay
What is observer drift?
when observers become inconsistent in their observations (ex: becoming more strict or lenient in their categorization of behaviour)
What are the confounding variables related to regression towards the mean?
tendency for extreme scores on any measurement to move toward the mean (regress) when the measurement procedure is repeated
How is regression towards the mean also called?
Statistical regression
What are order effects?
participation in one treatment has influence in participation in the following treatments
Any change in performance caused by participation in other treatments = order effects
What is fatigue?
decline in performance as participant moves through treatments
What is practice?
improvement in performance as participant gains experience through treatments
What is carry-over?
effects on one treatment linger in the following treatment and affects its performance
What are contrast effects?
type of carry over effect (EX: coming from a bright VS a dark room and entering a dimly lit room - perception will not be the same)
What are progressive error effects?
Carry over effects are caused by experiencing other treatments, other effects (fatigue, practice) are called progressive error effects and are due to simply being in the study
Name all time-related factors
History, maturation, instrumentation, regression
Name all order effects
All effects directly relates to experience in other treatments
What are the 3 methods to control for environmental factors?
- Randomization
- Holding constant
- Matching across treatments
What are the 3 main ways to control for time related or order effects?
Controlling time
Switch to a betwee-subjects design
Counterbalancing
What is controlling time?
Controlling the time it takes to complete the study (increases the potential of order effects)