Validity And Reliability Flashcards
(36 cards)
Reliability
The extent to which a test produced consistent results
Internal reliability
The extent to which the test is consistent within itself
E.g. whether the different questions in a questionnaire are all measuring the same thing
External reliability
The extent to which the test is consistent over time
E.g. if we repeated an IQ test, we would expect the same result on a different day
A cause of reliability issues is that instructions are not given in the same way.. how to overcome this?
Standardise the procedure
A cause of reliability issues is that variables are not clearly defined.. how to overcome this?
Operationalise variables(specific)
A cause of reliability issues is that the research has only been conducted once (not replicated) .. how to overcome this?
Not been proven that the results have internal reliability , so repeat the study
Measuring reliability: Experimental methods
In experimental methods such as lab, field or natural experiments, we can assess reliability by replicating the experiment.
If the study is reliable, the results should be consistent each time.
Measuring reliability:
Non-experimental methods
Non-experimental methods such as observations, interviews and questionnaires can also be replicated to test for reliability. However, there are also other ways to test their reliability
What are the 3 ways to measure reliability on-experimental methods?
Test-Retest reliability
Split Half reliability
Inter-Rater reliability
Test-Retest reliability
The measure is administered to the same group of people twice
If the results on the two tests are similar, we can assume the test is reliable
Split Half reliability
Splitting a test into two halves, and comparing the scores in both halves
If the results in the two halves are similar, we can assume the test is reliable
Inter-Rater reliability
If the measure depends upon interpretations of behaviour, we can compare the results from two or more raters
If there is high agreement between the raters, the measure is reliable
Validity
The extent to which a test produced accurate results
Internal validity
Internal validity asks whether we actually measured what we intended to measure.
It is concerned with whether we can be certain that it is the IV that caused the change in the DV
What can internal validity be affected by
A lack of mundane realism
This could lead the participants to act in a way which is unnatural, this making the results less valid
Internal validity can also be affected by extraneous/confounding variables
How can situational variables affect the internal validity of a study?
(anything to do with the environment of the experiment e.g. time of day, temp, noise levels)
Something about the situation of the experiment could act as an extraneous variable if it has an effect on the DV
e.g. Poor lighting could affect participants performance on a memory test
How can situational variables be overcome?
Standardise procedures which ensure all participants are tested on the same conditions
How can participant variables affect the internal validity of a study?
(Anything to do with differences in the participants e.g. age, gender, intelligence)
Differences in the participants cause the change in the DV
e.g. One group may perform better in a memory test because they are younger on average
How can participant variables be overcome?
Participant variables can be completely removed by using a repeated measures design
Matched pairs could also be used
How can investigator effects affect the internal validity of a study?
(How the behaviour and language of the experimenter may influence the behaviour of the participants)
Also known as researcher bias
Leading questions from the experimenter may consciously or subconsciously alter how the participant responds
How can investigator effects be overcome?
Using a double blind technique
This is when the person who carries out the research is not the person who designed it
How can demand characteristics affect the internal validity of a study?
(Participants guessing the aim of the study and thus changing their behaviour according to the aim)
The structure of the experiment could lead to the participant to guess the aim of the study and high may cause them to change their behaviour
How can demand characteristics be overcome?
When designing the study, it is important to try and create a situation where the participants will not be able to guess what the aim of the study is
A double blind design could also help this issue
How can participant effects affect the internal validity of a study?
(Participants are aware they are in an experiment, may behave unnaturally)
They may want to please the experimenter (please you effect)
They may decide to go against the experimenter’s aims and act in a way which spoils the experiment (screw you effect)
