methods - longitudinal Flashcards
what is a longitudinal study?
involve following the same individual(s) over a period of time, gathering data from them more than once and comparing any changes over time
examples of longitudinal studies in clinical psychology?
bradshaw - carried out a 3 year case study on how effective cbt was when used to treat a woman with sz
williams - same tests were used three times over the course of 11 weeks to measure depression (before cbm-i, after 7 day cbmi- intervention, after 10 week icbt intervention)
what is a strength of longitudinal studies?
As the same pps are measured throughout the duration of the study, there is no problem with individual differences, this means there is high internal validity
As the same standardised tests are used at each point of measurement, the method is reliable because the method is replicable
what are weaknesses of longitudinal studies?
Because the pps are being measured at different time intervals over a long period of time, there is a high chance of attrition. This reduces the sample size, therefore reducing the generalisability. People may move away, want to drop out due to boredom or personal problems, become too ill etc.
Because the pps are measured over a long period of time, gathering and analysing the data is time consuming and may have a high cost (paying researchers and use of equipment)
