Validity Flashcards
Internal validity
This concerns legitimacy and what is being measured in the actual study. It is the extent to which a test/study is investigating the true effect of the IV on the DV. The researcher must make sure they are observing/measuring what they intend to.
Internal validity can be affected by
Investigator effects
Demand characteristics
Confounding variables
Social desirability bias
Lack of operationalisation
Different ways of Assessing internal validity
Concurrent validity
Face validity
Concurrent validity
This is a way of establishing the internal validity of a new test, (e.g. a new IQ test) whereby the scores gained from this new test can be compared against an older, established test where the validity is already known (e.g. Stanford-Binet IQ test). If the scores from both tests are similar and a positive correlation coefficient of +0.8 or greater is found, then the new test is judged as having high internal validity.
Face validity
This is a way to measure whether the test or measuring instrument is measuring what it should e.g. a questionnaire. One or more researchers/experts in the field can examine the test items/questions to see whether they are measuring what it set out to. They would do this by looking at the questions on a questionnaire and seeing, “on the face of it” whether the questions appear to be measuring what they should. For instance if we were to measure IQ, we could get a specialist psychologist in the field to examine each question in the IQ test and see whether each question is really measuring IQ or not. This would involve a quick look over the questions.
How to improve internal validity
Concurrent validity can be improved (depending on the research method used). For instance if low concurrent validity is found on a questionnaire, then the researcher could remove questions that seem irrelevant or ambiguous, and then test the concurrent validity again.
Face validity can be improved (for a questionnaire) by an expert in the field examining all of the questions on the questionnaire. They might decide that some of the questions are not a good measure of the topic being investigated e.g. IQ, and they then might improve/rewrite/re-word certain questions again. This will help improve face validity.
External validity
Refers to factors outside of the research setting. How well can the results gained from the research be generalised to other people, settings and eras
Ecological validity
Ability to generalise research findings to other settings and contexts, in particular top everyday life situations and settings (high in mundane realism)
Temporal/Times validity
Findings from a study are true over a period of time can be generalised to others historical time eras
Assessing external validity
• Meta Analysis can be conducted, whereby a comparison of findings (from a range of different research studies that have investigated the same hypothesis) can be compared. Consistent findings from different research studies that have occurred across populations, locations and periods of time indicate high ecological validity e.g. Van Ijzendoorn who conducted cross cultural studies into the Strange Situation study.
• Consider the environment that the study was conducted in. The environment should be one that is quite naturalistic if the psychologist wishes to have high ecological validity. A longitudinal study might be low in ecological validity because the setting is not very natural and quite artificial
• Assess how the dependent variable was measured For instance the task that participants are given to do in the study and the way it is measured can affect the external validity. The task should have high mundane realism and should reflect the task that a person would be expected to do in everyday life, e.g. memorise a list of words
• Assess whether the participants were behaving as natural as possible, and ensure that demand characteristics have been kept to the minimum. Participants should not be aware of the true aims of the study because they will change their behaviour and this would have a dramatic effect on the DV which could result in low validity.
Improving external validity
• In order to improve external validity, demand characteristics could be reduced. This could be done via using a double blind procedure whereby the psychologist and the participants do not know the true aim of the study, and therefore no one is really aware of what the research is investigating. A single blind procedure means that only the participants do not know the true aim of the study, they are deceived into believing the study is about something else.
• In order to improve ecological validity, some pieces of research should be carried out in naturalistic settings. For instance a laboratory experiment could be carried out in a more natural setting such as a field experiment instead, or an observation could be carried out in a covert manner. A field experiment and a covert observation could ensure that participants behave more naturally and therefore this could lead to an improvement in ecological validity.
