observational studies

Question 1

descriptive studies

Answer 1

describe a phenomena, not a test (for cause and effect)
ex: case reports and case series, ecological studies

Question 2

ecological studies/fallacies

Answer 2

studies: examining group level data (meat consumption and cancer rates)
fallacy: mistaking group level trends for individual level truths

Question 3

analytical studies

Answer 3

examine exposure + outcome relationship, ex: cross sectional, case control, cohort

Question 4

cross sectional study

Answer 4

data is collected at a single point in time, measures the prevalence of an outcome, CANNOT establish if outcome or exposure came first

Question 5

case control study

Answer 5

participants are selected based on disease status, looks back to determine past exposure, measures using the odds ratio (OR), limitations: cannot calculate disease prevalence, high risk of recall bias, hard to establish temporality

Question 6

temporality

Answer 6

cannot determine if exposure or outcome came first

Question 7

cohort studies

Answer 7

participants start without the disease and followed over time, measures relative risk (RR) to determine how much more likely an outcome is

Question 8

prospective cohort study

Answer 8

follows participants into the future

Question 9

retrospective cohort study

Answer 9

uses past data to form cohorts

Question 10

establishing causation from observational data

Answer 10

correlation does not imply causation, however causality is more likely when: strong association, findings are consistent across studies, dose response relationship is observed, exposure precedes outcome, a valid biological mechanism explains the risk