Lecture 7 - Critical Aprraisal Of Observational Studies Flashcards
What is evidenced based practice?
Descisions about health care are based on the best available , valid and relevant evidence
What is critical appraisal?
The process of carefully and systematically examine research to judge its trustworthiness, and its value and relevance in a particular context
When developing a research question, what format do you use?
PICO
What is the meaning of PICO in developing a research question?
P - Patient/population
I - Intervention/exposure
C - Comparison
O - Outcome
How does quality of evidence relate to risk of bias?
As risk of bias increases quality of evidence reduces
Why may articles get rejected?
Study not of an important scientific issue
Study didn’t actually test authors hypothesis
Sample size too small
Study was uncontrolled or inadequately controlled
How do you Critically appraise a study?
Determines whether there is selection bias (is there a systematic difference between the people that have been selected and those that have not been selected)
Data collection (how was the data collected)
What is usually not able to be investigated in observational studies?
Associations can be investigated
CAUSATION CAN NOT
When apprasing a case-control study what is of big concern?
Recall bias
Misclassification bias
Interviewer/observer bias
Confounding
Is the exposure and outcome clearly defined?
Are the cases and controls clearly defined?
What is a case-control study?
When you get a group of people that have the case (i.e disease) and a control group of people (dont have disease)
You then ask these people if they have been exposed to the exposure being studied or not
BOOM
What is a Cohort study (retrospective/historical)?
Cohort studies are a type of longitudinal study—an approach that follows research participants over a period of time (often many years). Specifically, cohort studies recruit and follow participants who share a common characteristic, such as a particular occupation or demographic similarity.
Ask people if they have had the exposure, then see if they develop a new case
What needs to be considered when appraising a cohort study?
Selection bias
Response bias
Measurement bias
Healthy worker effect
Are the populations representative
Is the follow up long enough?
What is a cross sectional study/
Type of observational study. In a cross-sectional study, the investigator measures the outcome and the exposures in the study participants at the same time.
What needs to be considered when appraising a cross-sectional study?
Selection bias
How representative the sample is of the population
Response bias
Measurement bias
Confounding
