Reliability & Validity Flashcards
Reliability
How consistent or dependable test is
Internal reliability
Different parts of the test should give consistent results
Eg. If a IQ test contains sections of supposedly equal difficulty participants should achieve similar scores on all sections
The extent to which a test is consistent within itself
External reliability
The test should produce consistent results regardless of when it’s used
Eg. If you took the same IQ test on two different days you should achieve the same score
Refers to the ability of the test to produce the same results each time it is carried out
Inter-observer reliability
Test should give consistent results regardless of who administers it
Eg. If 2 researchers observe behaviour and categories infants as showing signs of a strong attachment or a weak attachment they should both record the same score
Validity
Refers to how all a rest measures what it claims to
Face validity
The extent to which the test looks to the participants like it will measure what it is supposed to be measuring
Concurrent validity
The extent to which the test produces the same results as another established measure
Temporal validity
The extent to which the test provides results that can be generalised across time
How can you improve reliability and validity ?
- Standardising research
- Operationalising variables
Standardising research
- Involves creating specific procedures which are followed every time the test is carried out
- ensures all the researchers will test all the participants in exactly the same way
- eg. Same environment, same time of day
- reduces the possibility of extraneous variables affecting the research thus it will help to improve external reliability and inter-observer reliability
Operationalising variables
Involves clearly defining all of the research variables
- eg. In a study of whether watching aggressive TV influences aggressive behaviour , these terms need to be defined
- aggressive TV can include cartoons or human actors ,one of these may influence human behaviour and the other may not
- aggressive behaviour could refer to physical and verbal aggression of just physical aggression
Clarifying this from the start improves the reliability and validity of the test
Methods used to assess/ensure reliability as
- inter-rarer reliability
- split half method
- test - retest method
Inter-rates reliability
Two or more interviewers/ observers must get the same outcome on 80% or more of the behaviours
Split half method
Compare an individual’s performance on two halves of a test
Test - retest method
A person repeats a test a month or so after doing the test the first time
