A" Research Methods Reliability and validity
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This document discusses the importance of validity and reliability in research. It addresses whether research tests truly measure what they aim to measure (validity) and whether the results are consistent (reliability). Specifically, it covers the concepts of internal validity, external validity, content validity, face validity, test-retest reliability, inter-rater reliability, and split-half reliability. The document emphasizes that research must demonstrate both validity and reliability to ensure the findings can be generalized and the measuring tools are sound.
A" Research Methods Reliability and validity
- 1. Validity! We need to find out if our research is sound. Do our tests measure what they claim to measure?
- 2. Are techniques used to collect data in tests, questionnaires, interviews and observations measuring what is claimed? For example was the Strange Situation really measuring attachment style?
- 3. We need to be able to measure or observe something time after time and produce the same or similar results
- 4. I want to measure intelligence. If the same person sits the test on several occasions and the results change each time, then that test lacks reliability
- 5. The test also arguably lacks validity because the scores are meaningless
- 6. If I test my participants again several months later and their scores remains consistent, I can say the test is reliable, but it might still lack validity.
- 7. Is an A level in Psychology a valid and reliable assessment of your performance in Psychology.
- 8. This measures consistency from one occasion to another – the same result should be found on different days, in different labs , observations or interviews, by different researchers I exposed these teenage brain cells to 1000 PowerPoint slides last Monday and they’re all dead I thought that was a fluke but they seem to be shrivelling after only five minutes!
- 9. Participants take the same test on different occasions – a high correlation between test scores indicates the test has good external reliability . Timing is crucial. Why? January June I hope that’s the right answer this time
- 10. This refers to the consistency of a researcher’s behaviour. A researcher should produce similar test results, or make similar observations or carry out interviews in the same way on more than one occasion. Thanks for taking part today. Any problems and I’ll be right over. Take your time. Right. Let’s get on. Fast as you can. How much longer before I can get in the pub and relax my facial muscles?
- 11. In observational studies this is known as inter-observer reliability – observers have to agree on what they see and carry out the same procedure Consistency between different researchers working on the some study is very important for reliability
- 12. 1. Increase reliability by standardising instructions 2. Carry out a pilot study to improve procedures and materials 3. You will be thoroughly trained in the use of materials and procedures prior to our study taking place
- 13. This measures the extent to which a test or procedure is consistent within itself, i.e., questionnaire items or questions in an interview should all be measuring the same thing Do you like to keep to deadlines? Do you get impatient driving? Do you like cheese? Do you like doing several tasks at once? Do you like chocolate? Do you get easily irritated? Are you competitive? This interviewer seems a little confused about Type A personality traits
- 14. Odds/Evens Top/Bottom Compares a participant’s performance on two halves of a test or questionnaire – there should be a close correlation between scores on both halves of the test. Questions in both halves should be of equal quality for good internal reliability.
- 15. Would you see this as bullying or horseplay in the playground? You would see this from your own subjective viewpoint – we’re biased by experience and expectation Observers must agree about what they are observing – they need to use standardised behavioural categories
- 16. Measuring Reliability Match the method of estimating reliability to the description Test-Retest reliability If the measure depends upon interpretation of behaviour, we can compare the results from two or more raters. If the results in the two halves 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 on the two tests are similar, we can assume the test is reliable Inter-Rater reliability The measure is administered to the same group of people twice If there is high agreement between the raters, the measure is reliable
- 17. The tool is measuring what it is intending to measure = = The findings can be generalized beyond the context of the research situation
- 18. Does our measuring tool appear to be doing what it should? Face validity: One or more judges assess whether the test seems appropriate and suggest changes if necessary
- 19. Does the content of a test cover everything in the area of interest? Content validity: More rigorous – experts in the field systematically examine the tool’s components and compare them with set standards They have to agree the content is appropriate
- 20. Improving internal validity • Single blind procedure - reduces demand characteristics • Double blind procedure ….
- 21. Population Validity Can we generalise findings from our research participants to other population groups?
- 22. Can we apply our findings to other contexts and situations outside of the research setting? Ecological Validity
- 23. Improving external validity • Sample must be representative of target population and be unbiased….. • Research situation must reflect real life situation e.g. debate over Milgram….Strange Situation