Quantitative - data collection issues: outcomes, measurement, reliability, validity

Question 1

What is the main outcome for a study called?

Answer 1

primary outcome

can also have secondary outcomes

Question 2

What do outcomes have to be?

Answer 2

• meaningful: outcomes have to be credible, meaningful and related to the issue of interest
• measurable
• responsive- change that occurs is demonstrated in the outcome measure
• measurements should be valid and reliable

Question 3

What is reliability?

Answer 3

addresses whether repeated measurements provide a consistent result given the same initial circumstances

Question 4

What is validity?

Answer 4

does your measurement, process or assessment actually measure what you intend it to measure?

Question 5

What is internal validity?

Answer 5

study results legitimate because of the way the study was conducted: did the IV really change the DV?

without internal validity you cant have external validity

Question 6

What are threats to internal validity?

Answer 6

• history: events happening outside study
• maturation: changes that happen over time
• testing: change due to experience of the test
• instrumentation: changes in measurement rather than change in status
• mortality: differences in study drop out
• selection bias: PPs different to non-PPs

Question 7

What is external validity?

Answer 7

or generalisability

-concerns whether results are transferable to other groups

Question 8

What are threats to external validity?

Answer 8

• selection effects: generalisability to other populations, when ideal sample population cant be obtained
• reactive effects: response to just being in a study (hawthorne effect)
• measurement effects: measurement and testing affects the generalisability