Studies Flashcards
RCTs
- Advantages
Maximizes internal validity
Gold standard for establishing casual relationship
Well defined study population (Strong evidence for those who fall into study criteria)
RCTs
- Disadvantages
Ethical Issues
Feasibility (Large sample size, cost)
Time
Prone to Type 2 Error
Hard to generalize
Observational Studies
- Advantages
Diverse populations
Exposure follows real world use of the drug
Broader group of comparison treatments
Longer observation window
Larger sample size (Good for rare events)
Lower costs
Observational Studies
- Disadvantages
Can not prove causal relationship
Selection bias
Misclassification bias
Confounding Variables
Prone to Type 1 Errors
Results can be overestimated
Cross-Sectional Studies
- Advantages
Exposure and Outcome data collected at same time
No risk of loss to follow up
Efficient in time and cost
Cross-Sectional Studies
- Disadvantages
Can not establish causation
Impractical for rare diseases
Small sample size, can miss events (Can draw from other samples to increase size)
Unknown if exposure or outcome came first
Case Control Studies
- Advantages
Can examine multiple risk factors for the same outcome
Good for rare outcomes or outcomes with long latency
Case Control Studies
- Disadvantages
Can only examine one outcome
Selection bias
Information bias (when identifying exposure to risk factors)
No easy way to estimate prevalence of disease or risk of the population
Cohort Studies
- Advantages
Can examine multiple outcomes for same exposure
Less risk of selection bias
Defines the incidence rate (Risk that is attributed to exposure)
Cohort Studies
- Disadvantages
Can not account for all potential alternative explanations (Confounding)
Needs large sample sizes (Especially for rare outcomes)
Prospective Cohort Studies
- Advantages
Information collected from study subject (Can clarify or add in additional info)
Data collection is not biased by knowledge of outcome
Prospective Cohort Studies
- Disadvantages
Extensive, especially if data collection is needed over a long period of time
Labour intensive
Can take several years to complete (Loss to follow up, or drop outs)
Retrospective Cohort Studies
- Advantages
Efficacy of time and costs
Retrospective Cohort Studies
- Disadvantages
Reliability of data collection (Is info accurate)
Unsure if patient took medication with fill history
Can exposure be characterized?
Administrative Health Records
- Advantages
Linkable Data
Large Sample Size
Inexpensive to use
Information on Health Care Utilization
Administrative Health Records
- Disadvantages
No validation of diagnostic information
Abscence of information for confounding (lifestyle, clinical)
Prone to instability
May not record all conditions
Electronic Medical Records
- Advantages
Diagnosis is more accurate
Additional info on confounding (smoking, alcohol, BMI)
Progress notes (More info on treatment plans)
Electronic Medical Records
- Disadvantages
Variability in terms
Not linkable
Other Sources (From RCTs)
- Advantages
Efficient (Time and cost is reduced)
Other Sources (From RCTs)
- Disadvantages
Data may not be compatible with research question
Records may be incomplete
Risk of type 1 (alpha) error
Data dredging
