Validity of Qualitative & Quantitative Methods (AQA GCSE Psychology)

 Validity refers to the extent to which a piece of research can be said to be ‘true’ i.e. a realistic measurement/explanation of behaviour within the context of the research process

For a piece of research to be valid it must reflect  how real, ‘actual’ people behave, think, respond etc. above and beyond the confines of the study itself

Lab experiments tend to use artificial tasks within a controlled environment i.e. they are not high in validity (they are, instead, high in reliability)

To preserve as much validity as possible within the experimental design, researchers must ensure the following:

• Independent groups designs should use random allocation to condition so that no bias intrudes upon the procedure i.e. the researcher does not choose which participants end up in each condition, they are selected at random

• Repeated measures designs should use counterbalancing to ensure that order effects do not interfere with the study i.e. half the participants experience condition A followed by condition B and the other half vice versa

• Matched pairs designs attempt to address issues with validity as they match one participant with another across conditions to factor out individual differences and order effects

The main issue with samples used in psychological research is that they tend to not be representative of the target population from which they are obtained, e.g.

• Researchers often use the easiest sample to obtain (students from the university in which they are based) which means that the sample is limited in terms of generalisability i.e. it only represents students from that city/area

• Opportunity/convenience sampling as outlined in the example above only uses participants available at the time of the study taking place, hence it will always exclude those who weren’t available to participate

One of the most representative sampling methods is stratified sampling which matches the target population proportionally e.g. if the target population is 58% female then the sample will be 58% female, etc.

Qualitative methods such as interviews and case studies are higher in validity than experimental/quantitative methods for the following reasons:

• Qualitative methods deal in descriptions rather than numerical data:

• Words add expression, explanation, and meaning, whereas numbers simply show a researcher what happened/how many/what percentage etc.

• Qualitative methods use small samples (sometimes, with case studies, just a single participant) so that data can be in-depth, insightful, subjective

• The more ‘real’ a method is (i.e. the more it matches real experience) the more valid it is, particularly in terms of ecological validity

Qualitative methods generate huge amounts of data which can be difficult to analyse and interpret due to its very subjective nature e.g. if a participant speaks in a particular tone of voice does it mean that they are bored? angry? upset? Or something else?