1. Classes of intervention studies Flashcards
(e.g. pre-experimental, quasi-experimental and true experimental designs; parallel group designs, cross-over designs, N-of-1 design, non-inferiority trials etc.)
What is a quasi-experiment?
An experiment with two groups, but no randomisation
What is a pre-experimental design?
An experiment with only one group (no control)
What is the primary aim of a pilot study?
Focus on the feasibility of the definitive trial
methods can be mixed with some qualitative elements
What do the letter in PICOT stand for?
P : Population or patient (including disease, disorder of interest)
I : Intervention/prognostic factor or exposure of interest
C : Comparator; another intervention placebo or “care as usual”
O : Outcome (primary)
T : Type of study (such as parallel group design, randomized)
What is the difference in research question between a non-inferiority and a equivalence trial?
Non-inferiority = asymmetric Equivalence = symmetric
What is the benefit of a factorial design?
Both the separate effect of each intervention and the benefit of receiving the intervention together.
What is a disadvantage in the factorial design regarding sample size?
The assumption that there is no interaction is often false, but this can often only be determined after termination of the study and would have required a larger sample size.
Why is it sometimes preferable to randomise a group rather than individuals? (2)
- Contamination (e.g. diet)
- Only possibility (classes)
What options in stepped wedge cluster designs are there? (4)
- Parallel cluster study
- Parallel cluster study with a baseline period
- Stepped wedge study
- Stepped wedge study including transition period
What do you need to determine in a stepped wedge cluster design? (4)
- Number of clusters
- Number of steps
- Length of steps
- Number of observations per cluster
What is an explanatory trial?
Tests a causal research hypothesis under (near) ideal circumstances
What is a pragmatic trial?
Helps choose the best option for care under usual circumstances
What is the difference in research questions in explanatory vs pragmatic designs?
Can this work under ideal circumstances vs does this work under usual circumstances?
What is the difference in participants in explanatory vs pragmatic designs?
Pragmatic: all candidates with the condition of interest
Explanatory: just high-risk, highly responsive candidates with high compliance (pre treatment appointment keeping)
What is the difference in interventions in explanatory vs pragmatic designs?
Highly flexible vs strict instructions
Full range of caregivers vs specially trained and closely monitored
Usual care vs placebo
