Definition of validity?
- the extent to which a given findings shows what it’s believed to show
- refers to the internal characteristics of a piece of research
Definition of a valid finding?
-one where there are no possible alternatives to the explanation provided by the researcher
Definition of internal validity?
- extent that the study tells us what we think it tells us
- whether there’s any other causes for the observed effects
What are threats to internal validity when a study is prolonged over time?
- history effect
- maturation effect
- regression to the mean
- testing effect
- instrumentation effect
Definition of history effect?
-event other than manipulation occurs between pretest and post-test and effects the study outcome
Definition of maturation effect?
-participants naturally change between pretest and post-test
Definition of regression to the mean?
-the likelihood that if participants do really bad at first they’ll improve
What is testing effect 1?
-participants perform better at a post-test because they had practice
What is testing effect 2?
-participants perform worse at a post-test because they got tired
What is testing effect 3?
-by doing a pretest participants are alerted to some aspects of the manipulation and pay more attention to these
Definition of instrumentation effect?
-performance at pretest and post-test differs because different measures are used
What are participant related threats?
- selection effect
- mortality
Definition of selection effect?
- participants in different conditions aren’t equivalent
- happens when random assignment fails
Definition of mortality?
- participants with certain characteristics drop out of the study
- non-random
Definition of external validity?
- extent to which results can be generalised beyond the context of the study
- samples have to be representative on theoretically relevant dimensions
What is the issue with student samples?
- issue when the process is expected to operate differently in a student population
- e.g. social influence
What are the different validity types under external?
- ecological
- temporal
- statistical conclusion
- construct
Definition of ecological validity?
- what may be true in one set of environmental circumstances may not be true in all environments
- mundane and experimental realism
Definition of temporal validity?
-what may be true at one time may not be true at all other times or any other times
Definition of statistical conclusion validity?
- reduced when inappropriate statistical procedures are used
- e.g. assumptions made by statistical test aren’t met by the data
Definition of construct validity?
-operational definitions of the IVs and the DVs fit the purpose of the study
Definition of content validity?
-ability to include/represent all aspects of the construct you’re trying to measure
Definition of content validity?
-ability to include/represent all aspects of the construct you’re trying to measure
Definition of concurrent validity?
-ability to distinguish between groups that should theoretically be able to be distinguished between
