RCTs Flashcards
What needs to be considered if RCT findings are valid and applicable?
Eligibility criteria, randomisation method, allocation concealment, blinding, follow-up
What is scientific method?
Ensuring research is not shaped by personal belief but grounded in measurable (empirical) evidence
Which types of bias can be present in experimental studies?
Selection, performance, detection, attrition
What is internal validity?
Extent to which a causal conclusion is warranted, determined by the extent to which the study minimises systematic error (bias, confounding, chance)
What is external validity?
Extent to which study can be generalised to different situations and people regardless of internal validity
What are the 3 types of intervention studies?
- Uncontrolled before and after
- Controlled before and after
- RCT
What is the benefit of a controlled compared to an uncontrolled intervention study?
- Regression to the mean could give an appearance of improvement in an uncontrolled study which is minimised with control groups
- Some confounding factors may be accounted for with comparing to a control group (eg seasonal)
How are RCTs beneficial to controlled clinical trials?
Participants in a controlled clinical trial are assigned to new treatment or control by themselves, dr or researcher - this could introduce selection bias
How could participants choosing their assignment to groups impact the study?
Selection bias - participants choosing active treatment might differ to those who do not
How could doctors choosing assignment to groups impact the study?
Might put those frail or unlikely to withstand new treatment in controls, or younger or sicker people in active treatment to give them a better chance
How could researchers choosing assignment to groups impact the study?
Might only select those who will do well to be in active groups
What are the key features of an RCT?
Randomisation of allocation to groups, allocation concealment, blinding and intention to treat analysis
What are the 3 sections of the CASP tool for RCTs?
Are the results valid?
What are the results?
Will the results help locally?
How do you look at choice of outcome measure of a study?
- Is it relevant to patients (clinical effectiveness or patient experience)
- If proxy, does it measure what it should?
- Type
- Needs to be reliable, valid, responsive
What makes an outcome measure reliable?
Able to produce consistent, reproducible estimates of true effect
What makes an outcome measure valid?
Measures the construct it claims to
What makes an outcome measure responsive?
Detects changes in construct to be measured over time
What ethical issues are related to RCTs?
Equipoise (reasonable belief that interventions are equal) is required to ethically randomise participants
What are the different choices of controls in RCTs?
- Current best practice
- No treatment: only if no current best practice and do not feel new treatment is effective!
- Placebo
What is allocation concealment?
The person recruiting to a trial does not know which group the participant will be assigned to