Critical Thinking

Question 1

What is a RCT?

Answer 1

“Randomized controlled trial”

• Participants randomly assigned into control or study group
• Control receives typically used treatment
• Investigational receives intervention being studied
• Considered the most rigorous study design

Question 2

What is the most rigorous study design?

Answer 2

RCT

Question 3

What is an observational study?

Answer 3

• Description of 1 or more groups from snapshot in time
• Exposure and disease status determined at a single point in time, a cross-section of the population
• Weakest epidemiologic study design

Question 4

What is weakest study design?

Answer 4

Observational

Question 5

What is the following type of bias:

Ascertainment

Answer 5

Ptn. w/ suspected outcome more extensively probed about symptoms / histories than others

Question 6

What is the following type of bias:

Confounding

Answer 6

Effect of one factor influences effect of another

Question 7

What is the following type of bias:

Detection

Answer 7

More Info is solicited from treatment than control group

Question 8

What is the following type of bias:

Late-Look

Answer 8

Info gathered at wrong (too late) time point

Question 9

What is the following type of bias:

Lead-time

Answer 9

All cases are not detected at same stage of disease: Early detection confused w/ longer survival

Question 10

What is the following type of bias:

Procedure

Answer 10

Subjects not treated same in both groups: one group gets more visits, more attention, etc.

Question 11

What is the following type of bias:

Proficiency

Answer 11

• Intervention not applied equally to subjects

- Due to skill, training or differences in resources or procedures used at different sites

Question 12

What is the following type of bias:

Recall

Answer 12

Knowledge of presence of disorder alters subject recall

Question 13

What is the following type of bias:

Sampling/Referral

Answer 13

Subjects not representative of population

Question 14

What is the following type of bias:

Selection

Answer 14

Non-random assignment to study group

Question 15

What is the following type of bias:

Susceptibility

Answer 15

Patients receive one intervention or another on basis of disease severity

Question 16

What is the following type of bias:

Hawthorne Effect

Answer 16

Subject knows being observed changing her behavior

Question 17

What is the following type of bias:

Pygmalion Effect

Answer 17

Researcher’s belief in efficacy of a treatment changes outcome

Question 18

What is prevalence?

Answer 18

Proportion of persons in population who have particular disease at specified point in time (point prevalence) or over a specified period of time (period prevalence)

Question 19

What is incidence?

Answer 19

The occurrence of new cases of disease or injury in a population over a specified period of time

Question 20

What is reliability?

Answer 20

Reproducibility, consistency

Question 21

What is accuracy?

Answer 21

Truth, absence of bias, validity

Question 22

What is precision?

Answer 22

Exactness in measurement

Question 23

Difference in sensitivity and specificity?

Answer 23

Sensitivity: Probability that test produces positive result when a patient is known to have ailment
Specificity: probability that test produces negative result when patient is ailment free

Question 24

What is a true positive?

Answer 24

True Positive: both disease positive and test positive

Question 25

What is a true negative?

Answer 25

True negatives: both test negative, disease negative

Question 26

What is mean, median, mode?

Answer 26

Mean: Average
Median: middle number
Mode: most frequently occurring number

Question 27

What are primary, secondary, and tertiary prevention?

Answer 27

Primarily: prevent disease occurrence (vaccinations)
Secondary: early detection (pap smear)
Tertiary: reduce consequences of disease (insulin)