Case Study Design Flashcards
Definition of a randomized control trial
Intervention study allocated randomly
Comparisons made between new and current/placebo
Definition of case control studies
Observational studies
Investigates factors associated with disease
Compares groups of people with and without a disease
Normally retrospective
Definition of an observational study
No intervention
Subjects observed in natural state
Definition of a cohort study
Investigates factors associated with disease
Follows up on healthy individuals and possible risk factors over time
Normally prospective, can be retrospective
Definition of a cross sectional study
Collect data for each subject at 1 points in time
What are the 3 properties of a randomized control trial
Interventional study
Intervention allocated randomly
Comparisons made between new and current/placebo
Why is randomization important
Patient characteristics don't affect what treatment they get Unbiased Balanced treatment groups Different in outcome due to treatment Test efficiency
Why is blinding important
When is blinding not possible
Treatment concealed from patient (single) and/or assessor (double)
Reduce bias
Possible due to randomization
Double blinding not always possible, needs a placebo
How do you analyze the results in a RCT
Intention to treat
-Analyse in random groups even if the participants don’t comply/switch treatments
Balance remains as a result
Fair test of offer of treatment
What are the properties of a case control study
Observational study, subjects observed in natural state
Investigates factors associated with disease
Group with disease (cases) compared against group without disease (control) with respect to risk factors
Retrospective
What are the pros and cons of case control studies
Negatives
- Choice of control group affects comparisons
- data reporting by subjects/records, can be incorrect/inaccurate/biased
Positives
-quick and cheap
What are the properties of a cohort study
Observational
Investigates factors associated with disease
Healthy individuals followed up to monitor disease state and possible risk factors over time
Normally prospective, can be retrospective
What are the pros and cons of cohort studies
Positives
-less biased answer due to prospective data collection
Negatives
- need large no to get enough with disease
- often need a long follow up
- need to stay in touch with patients
- can be expensive
What are the properties of a cross sectional study
What are the uses
Observational
Collect data for each subject at 1 point in time
Useful for
- measuring disease prevalence
- surveys of attitudes/views
