lesson 4 - types of validity - assessing and improving validity Flashcards
what is internal validity
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 ob the DV. the researcher must make sure they are observing/measuring what they intend to
what can internal validity be affected by
investigate effects
demand characterisitcs
confounding variables
social desirability bias
lack of operationalisation
what is concurrent validity and how can u improve it
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.
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.
what is face validity and how can you improve it
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.
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.
how to reduce investigator effects
double blind procedure
uniform
script
same person
researcher conduct same study
remove researcher from study
how to reduce demand characteristics
double blind
covert observation
give each pp an IV
how to reduce confounding variables
matched pps design if repeated measures
lab exit
highly controlled
use a pilot study
what is external validity
External validity is the extent to which you can generalize the findings of a study to other situations, people, settings, and measures. I
types of external validity
ecological
temporal
ecological validity
ability to generalise research findings to other settings and contexts in particular to everyday life situations and settings/ high in mundane realism this increases ecological validity
temporal validity
findings from a study are true over a period of time and can be generalised to other historical time eras
how can u assess external validity
meta analysis whereby a comparison of findinf=gs from a. range of diff research studies that have investigated the same hypothesis can be compared. consistent findings from diff research studied that have occurred across populations.locations and periods of time indicate high ecological validity eg van who conducted cross cultural studies into the strange situation
consider the environment the study was conducted in. the environment should be one that us quite naturalistic if the psychologist wishes to have high ecological validity. a lab study might be low in ecological validity because the setting isn’t very natural and quite artificial
assess how the dependent variable was measured. eg the task that pps are given in the study and the way its measured can affect the external validity. the task should have high mundane realism and should reflect a task that the person would do in everyday life
assess whether the pps were behaving as natural as possible and ensure demand characteristics have been kept to the minimum. pps shouldn’t be aware of the true aim 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
how to improve external validity
reduce demand characteristics
can be done using a double blind procedure whereby the psychologist and the pps don’t know the true aim of the study and therefore no one is rlly aware of what the research is investigating. a single blind procedure means that only the pps don’t know the true aim of the study they are deceived into believing the study is ab smth else
in order to improve ecological validity some pieces od research should be carried out in naturalistic settings. eg lab exit can be carried out in a. more natural setting such as a field exit instead of an observation could be carried out in a covert manner. a field experiment and a covert observation could ensure pps behave more naturally and therefore could lead to an improvement in ecological validity
