Epidemiology

Question 1

PICO

Answer 1

• population
• intervention
• comparison (or control group)
• outcome

Question 2

A period of inactivity between stimulation and response

Answer 2

latency period

Question 3

In clinical studies, what must be considered to ensure adequate long-term follow up duration?

Answer 3

latency period

Question 4

A type of study that divides participants into a group that receives an intervention and a group that does not receive an intervention

Answer 4

clinical trial

Question 5

A type of study that divides participants into a group that has had an exposure and a group that has not had an exposure

Answer 5

cohort study

Question 6

A type of study that divides participants into a group that has a particular outcome and a group that does not have the outcome

Answer 6

case-control

Question 7

The group in a clinical trial that do NOT receive the intervention

Answer 7

control group

Question 8

The group in a case-control study that do NOT have the outcome being studied

Answer 8

control group

Question 9

An observational study that looks at disease PREVALENCE in exposed vs not exposed groups at a specific point in time.

Answer 9

cross-sectional study

Question 10

An observational study that looks at exposure PREVALENCE in those with disease and those without disease.

Answer 10

case-control study

Question 11

An observational study that looks prospectively at the outcome INCIDENCE in exposed and not-exposed groups.

Answer 11

prospective cohort study

Question 12

An observational study that looks retrospectively, using medical record review, at the outcome incidence in exposed and not exposed groups.

Answer 12

retrospective cohort study

Question 13

An experimental study that looks at the outcome in an intervention group compared to a control group

Answer 13

randomized controlled trial

Question 14

Study that uses odds ratio to determine if an exposure is associated with an outcome

Answer 14

case-control study

Question 15

This type of study can be prospective or retrospective

Answer 15

cohort study

Question 16

This study generally examines a small population group over a short period of time (less cost) and evaluates the association between multiple exposures and one outcome

Answer 16

case-control study

Question 17

This study generally examines a large population over a long period of time (more cost) and determines how one exposure is associated with multiple outcomes

Answer 17

cohort study

Question 18

In cohort studies, the study sample is selected based on

Answer 18

exposure to a risk factor

Question 19

The study that selects the sample according to having a disease or not, then determining which participants were exposed to a risk factor.

Answer 19

Case-control study

Question 20

Gold standard study for testing interventions

Answer 20

Randomized controlled trials

Question 21

Study participants do not know whether they are part of the control or treatment group

Answer 21

single-blind study

Question 22

Neither the researchers not the study participants know which study participants are part of the control group or part of the treatment group

Answer 22

Double-blind study

Question 23

Neither researchers, participants or data analysts know which study participants are part of the control group or the treatment group.

Answer 23

Triple-blind study

Question 24

The gold standard for blinding when studying treatment outcomes.

Answer 24

Double-blind study

Question 25

An experimental study design in which each participant switches from the intervention group to the control group or vice versa WITH a washout period.

Answer 25

Crossover design

Question 26

An experimental study design in which multiple interventions are studied simultaneously by assigning participants to various combinations of interventions and placebo.

Answer 26

Factorial design

Question 27

An experimental study design in which the unit of randomization is a group rather than an individual participant.

Answer 27

Cluster design

Question 28

Study participants are analyzed according to the group they were orginially randomized, regardless of whether they actually received the intervention or dropped out of the study.

Answer 28

Intention-to-treat analysis.

Question 29

Intention to treat analysis helps reduce what kind of bias?

Answer 29

Selection bias

Question 30

Intention to treat analysis is susceptible to what type of error?

Answer 30

Type II error - including patients who did not adhere to treatment can weaken the effect size and make the treatment appear less effective.

Question 31

Investigation of the heterogeneity of results in a study or recognizing significant discrepancies or similarities in the treatment outcome among different subgroups of patients

Answer 31

Subgroup analysis

Question 32

This type of study is conducted to increase statistical power and achieve more precise results

Answer 32

Meta-analysis

Question 33

Validity of a study is limited by:

Answer 33

- high random errors - biases - confounding

Question 34

Error that occurs due to chance and/or limitations of precision

Answer 34

Random error

Question 35

Random error can be reduced by:

Answer 35

Repeated measurements and averaging over a large number of observations

Question 36

An error in the study design or the way in which the study is conducted that causes systematic deviation of findings from the true value.

Answer 36

Systematic error (bias)

Question 37

Bias where individuals in the sample group are not representative of the population from which the sample is drawn because sampling or treatment allocation is not random

Answer 37

Selection bias

Question 38

Bias that occurs when certain individuals are more likely to be selected for study group, resulting in a non-random sample.

Answer 38

Sampling bias (ascertainment bias)

Question 39

A type of non-response bias of selective loss of participants to follow up (different prognosis)

Answer 39

Attrition bias

Question 40

A type of bias where individuals in sample groups are drawn from a hospital population and are more likely to be ill than individuals in the general population

Answer 40

Berkson bias (bedside bias)

Question 41

Type of performance bias in which subjects change their behavior once they are aware that they are being observed.

Answer 41

Hawthorne effect

Question 42

This bias occurs when patients or investigators decide on the assignment of treatment and this affects the findings; subjects in the treatment group spend more time and have highly specialized care compared to the control group.

Answer 42

Procedure bias

Question 43

A type of bias in which awareness of a condition by subjects changes their recall of related risk factors or recall of a certain exposure

Answer 43

Recall bias

Question 44

A bias in which the personal beliefs of study participants and/or investigators influence the results of the study

Answer 44

cognitive bias

Question 45

A type of cognitive bias in which the measurement of a variable or classification of subjects in influenced by the researcher's knowledge or expectations.

Answer 45

Observer bias or observer-expectancy bias (pygmalion effect)

Question 46

Any third variable that is associated with the exposure and the outcome by is not on the causal pathway between exposure and outcome

Answer 46

confounder

Question 47

This group of bias occurs during the analysis of the results phase of the study and multiple variables act as confounders, distorting the effect between the exposure and outcome of interest

Answer 47

Confounding bias

Question 48

What are some ways to minimize confounding in study design?

Answer 48

- randomization - cross-over study design - matching study participants

Question 49

This type of bias occurs in studies with screening tests when during the survival analysis, the survival time is overestimated because of early diagnosis through screening rather than reflecting an actual delay in mortality

Answer 49

Lead time bias

Question 50

A type of bias in which survival time is overestimated because screening tests have a higher probability of detecting slowly progressive cases which have a longer asymptomatic phase and better prognosis than rapidly progressive cases

Answer 50

Length-time bias