Clinical - Primary and secondary data

What is primary data?

Data you collect yourself

What is secondary data?

Data previously collected in another study/situation

Give some examples of studies using secondary data.

- Carlsson

Give some examples of studies using primary data.

- Rosenhan

- Brown

Give some examples of studies using both primary and secondary data.

- Heston (records and interviews)

- Carol (records already recorded and interviews/qnnaires during study)

- Twin studies e.g. Gottesman (whether someone is a twin, then the actual studies)

What are some strengths of using primary data? Include specific examples to clinical.

- Internally valid - experimental design likely measures behaviour you are interested in (Brown removed women with depression from his study as he was measuring its development)

- Reliability - performing a study yourself means you can put in place controls to replicate the study - standardised procedure (cannot be sure that secondary data uses standardised procedure as you did not perform it)

What are some weaknesses of using primary data? Include specific examples to clinical.

- Only one study so likely has issues with generalisability (e.g. Carol has very low generalisability as case study design - how applicable then are her results on CBT to others?)

- Gathering primary data takes time and money (e.g. Carol was followed for 3 years and lots of data had to be assessed. Using secondary data means that you only need to assess pre existing results rather than plan and carry out a complicated and expensive study)

What is a strength of using secondary data? Include specific examples to clinical.

Lots of different studies could give a more representative view of behaviour/condition etc, due to larger samples. (Carlsson collated many studies looking at NTs and S1 which means his sample is larger and thus more representative. He also used different kinds of data collection which means he gains a more holistic view of NTs effect on S1)

What are some weaknesses of using secondary data? Include specific examples to clinical.

- Low internal valid - data from other studies may not be measuring exactly what you are looking at (e.g. cannot be sure all studies Carlsson looked at actually measured NTs effect on S1. Some studies used SPECT rather than CAT scans - lower res means can we draw same conclusions?)

- Cannot be sure what controls etc were in place in other studies (e.g. when comparing different studies on progression of depression, you cannot be sure that extraneous variable such as medication taken are controlled for)

- Different types of data can be difficult to assess in relation to your study (Case study data can be highly specific and difficult to make comparisons e.g. comparing Carol's emotional progress to another person is harder than comparing statistical progress)