Timed Essay Flashcards
What is epidemiological bias?
Systematic error in design, analysis or interpretation that leads to inaccurate conclusions.
What is selection bias?
Systematic difference between the characteristics of the participants and the population, an inaccurate representation.
What is information bias?
Error in measurements of exposure, outcomes or confounding.
What is confounding?
When a third factor influences the observed relationship between exposure and outcome leading to an incorrect interpretation of the association.
What is Simpson’s paradox?
A correlation present between may disappear or are reversed when the groups are recombined
What statistical test can be done to assess bias or confounding?
Chi-squared
T-test
Logistical regression
Sensitivity analysis
Subgroup analysis
What is sensitivity analysis?
Changes in study factors or assumptions can influence the results.
What is subgroup analysis?
How small changes between group in population affect the outcome
What is chi-squared?
Association in of categorical data.
Whether the observed and expected values have a difference which is significant and not due to chance.
What is a t-test?
Association of continuous data.
Compare 2 groups and see if the observed differences are significant.
What is logistic regression?
Used to adjust for confounding variables.
Studies how changing variables will change the outcome of a binary event.
Outline the main points of the self-reported shift work and belief on cancer causation.
Participants were given a questionnaire on whether they believed that shift work patterns caused cancer.
Then they were asked to self-report their work shifts.
This was compared to their actual shift patterns
This was to test whether belief affected the way they recalled, the likelihood of them getting cancer or recall changing belief.
A significant association between belief and recall bias.
No proof to show recall changed belief.
Outline the study on biomarkers in bias and confounding?
Strengthen the statistical association
Reduce random error
Increase bias and confounding due to often being used in a small sample size.
This is because biomarkers can be both exposure and outcome.
Outline the meta-analysis on bias and confounding in IBD studies.
A random sampling of 160 observational studies.
67/160 Confounding
89/160 Bias
Reporting the issues in discussion was very low.
Outline the recall bias study done on alcohol consumption before an injury among emergency department patients.
Reporting drinking for the same 6-hour period every day going back a week.
Vancouver and Victoria
Estimate drinking frequency and heaviness.
3 days less biased after that accuracy decrease drastically.
Outline information bias in gynaecological studies.
Misclassification is unmatched for the exposed and unexposed.
Confounders unmeasured and unmatched.
Leads to bias in public health.
What do longitudinal rely on?
Commitment of the participants at the start as in the follow up.
What is covariates?
Joint variability for 2 variables
What is a validation study?
Assess the validity of a test or instrument.
What is a calibration equation?
Compares the measured values of an instrument to the standard allowing to correct any mistakes.
Meta-analysis of the association of vaccines and autism.
Not associated.
5 case-controlled and 5 cohort.
Report published in 1998.
Massout break in 2019 in the US.
Parental anxiety and public panic.
Cost of outbreak control and changing public beliefs.
How to encourage correct influence on public health?
Encourage collaboration
Regular monitoring to account for emerging bias.
Transparent reporting
Peer review
What can happen when epidemiological studies are in correct on public health?
Incorrect diagnosis and intervention, which can be dangerous and expensive.
What is the definition of reliability?
Refers to the consistency.
Measurement to produce similar results under different conditions over time.
