Module #6: Research Designs Flashcards
What is internal validity?
The degree or extent to which the differences in the DV are due to the IV and not some other variable
What is external validity?
The degree to which the findings are generalizable to other members of the population
What is history threat?
Example.
any event occurring in the experiment other than the IV or outside the experiment that may account for the results. History refers to events common to all subjects.
Example: Natural disaster, global pandemic, etc.
What is maturation threat?
Example.
a change in participants purely as a result of the passage of time (e.g. growing older, wiser, tired, etc.)
Example: A Longitudinal Panel Study
What is differential selection threat?
Example.
systematic differences in groups on the basis of the selection or assignment of subjects.
Example: Including two of one instructor’s same class; although the class and material is the same, the students and their academic levels are not
What is reactive arrangement threat?
Example.
participants’ awareness that they are participating in an investigation may influence their actions, feelings, and attitudes.
Example: participants may answer questions in a more desirable way since they know there is an evaluative component.
What is testing threat?
Example.
effects of taking a test one time on subsequent performance on a test
Example: A group familiarize themselves with the questions and formats which naturally improves scores during posttest
What is instrumentation threat?
Example.
aspects of the instrument used that may affect results and interpretation (e.g. reliability, validity)
Example: If a researcher uses two different tests, one for the pretest and one for the postttest that are not of equal difficulty
What is statistical regression threat?
Example.
tendency for extreme score to revert (or regress) towards the mean of a distribution when the measurement device is re-administered.
Example.
What is attrition threat?
Example.
systematic differences between individuals who drop out of the study and those who remain in.
What is diffusion of treatment threat?
Example.
interference when the intervention given to one group is also provided accidentally to all or some of those in the control group.
Example: Powerpoint example - someone gives it to the control that was not supposed to receive it.
What is experimenter effects threat?
Example.
tendency of the experimenter to unintentionally distort the procedures or results of an experiment based on the expected outcome of the study.
What is implementation fidelity?
failure of the experimenter to deliver the program or intervention as intended/designed.
What are key characteristics of internal validity?
Commonality = must impact more than one or two individuals in order to be a threat
Systematic Differences = must result in differences that are systematic (e.g. impacts control group but not experimental group)
Impact on the mean = must result in changes to a mean
What are key characteristics of external validity?
Causation = includes no inference about causation
Interpretation = how might this [the threat] change the results in another context (time place, etc.) with another population (differing in age, race, years in service, etc.)
