Bias & Causality

-statistical inference that suggests the exposure produces the effect based on: theory, scientific models, biology

-a statistical inference that suggests the effect is more likely with a particular exposure

Which form of association occurs by chance or bias?

a) causal association

b) confounded association

c) false association

Which form of association is caused by the correlation of a third variable?

a) causal association

b) confounded association

c) false association

Which form of association confirms the criteria of causality?

a) causal association

b) confounded association

c) false association

-occurs when the relationship between exposure or treatment and outcome is affected by another variable or a group of variables.

What is true of confounders?

-occurs when procedures are followed in selecting study participants such that participants who get selected in the study are either more likely or less likely to experience the outcome than those not in the study sample.

-when participants themselves decide to participate in or drop out of a study

-if a patient is referred to another provider or referred to laboratory tests because of an exposure to a drug

-errors in measurement regarding information on the study participants

-type of measurement error due to misclassifying exposed as unexposed

-occurs when participants in a research study or clinical trial do not accurately remember a past event or experience or leave out details when reporting about them

-cases are given more importance than controls in collection of information, or when the exposed participants are followed more closely than the unexposed

Which methodology of controlling for bias involves assigning individuals to a treatment or control group based on a mechanism that gives the same probability of being in either of the two groups?

a) blinding

b) randomization

c) restriction

Which methodology of controlling for bias involves selecting subjects who have the same value for a variable that might be a confounder?

a) blinding

b) randomization

c) restriction

Which methodology of controlling for bias involves ensuring that the patient or data collector is ignorant of the treatment assignment?

a) blinding

b) randomization

c) restriction

Which methodology is aimed to correct information bias at the study design-level?

a) blinding

b) randomization

c) restriction

-Involves identifying some characteristic that is alleged to be a source of bias (i.e., a confounder) and matching cases with controls or exposed subjects with unexposed subjects with respect to that characteristic

-Analysis of the exposure-outcome association is performed within each of several subgroups created based on the (proposed) confounding variable

-Can combine effect estimates for all strata into one weighted summary effect measure (called a pooled or common effect

What do we use to control for multiple confounders at the same time?

-designed to assign participants to an assigned treatment group based on observable characteristics; patients with similar probabilities are considered similar patients.

what are the two main important steps in risk adjustment?

-The process by which the health status of a population is taken into account when making meaningful comparisons of patterns or outcomes of care or setting capitation rates

Which step of risk adjustment involves creating or setting a measure to define risk or severity?

Which step of risk adjustment involves the researchers using the adjusted risk severity?

________ exclude patients with comorbidities while _________ include patients to examine real-world outcomes.

-–based on diagnoses codes ICD10CM (e.g., Charlson comorbidity index, Elixhauser index, APACHE)

-based on medication use (e.g., chronic disease score (CDS), RxRisk score)

What is the purpose of propensity scores?

Patients with similar probabilities are considered what?

How can we use propensity scores?

-Systematically repeating the analysis by varying assumptions eachtime, in order to assess how sensitive the results obtained are to thevariations in model assumptions and whether the results areconsistent across the variations in assumptions

-the process by which the health status of a population is taken intoaccount when making meaningful comparisons of patterns oroutcomes of care or setting capitation rates

What's another term for risk adjustment?

______ are unrelated to causality to the principal diagnosis, but may be important risk factors?