Final Exam 3

Question 1

What are observational pros

Answer 1

High sample power, exclusion/inclusion are relaxed causing increased external validity, measure long-term outcomes and detect more rare events, completed quickly

Question 2

What are observational cons

Answer 2

Biases cannot be easily removed, observational trials are subject to missing or incorrect data, little control over the variable, can only establish associations (no causality/ correlation does not mean causation)

Question 3

What are common types of internal validity flaws in observational trials

Answer 3

Selection bias, confounding bias, information bias

Question 4

What is selction bias, what are the types of selcetion bias

Answer 4

The method of selecting subjects leads to a result that does not reflect the general population/ sampling bias, detection bias, response bias

Question 5

What is confounding

Answer 5

infuential risk factor/exposure that is unequally distributed between groups leading to incorrect conclusions that the actual exposure/risk factor is associate with the outcome

Question 6

How does selection bias become managed

Answer 6

Use objective criteria to identify cases and controls, inclusion/exclusion criteria must be a priority, need high participation rates to better validate survey data

Question 7

What are ways that confounding is controlled

Answer 7

Create inclusion/exclusion criteria to minimize variation (improve internal validity), matching: selecting a control for every case that is very similar, stratification: create subgroups, multivariable analysis: regression analysis that will inherently adjust for variances

Question 8

How can information bias be managed

Answer 8

use a prospective cohort design, observing and recording bias, record the reasons for loss to follow-up, observational trials have higher external validity