Chapter 7: Observational Studies

Question 1

Does descriptive studies generate hypotheses, true or false?

Answer 1

True

Question 2

Does analytic studies test hypotheses, true or false?

Answer 2

True

Question 3

What is descriptive epidemiology?

Answer 3

Means organizing, summarizing, and describe epidemiologic data by person, place, and time.

Question 4

What are descriptive factors?

Answer 4

Age, sex, and occupation (person characteristic)
Residence, work, environmental factors (place characteristics)
Clinical symptoms, diagnosis, reporting, testing (time)

Question 5

What study design is included in descriptive?

Answer 5

Ecological, case report, case series, and cross sectional.

Question 6

What study design is included in analytic?

Answer 6

Clinical trial, cohort, case-control.

Question 7

What are case reports and case series?

Answer 7

One report or more series focused on a specific disease or outcome, which typically occurs in a natural clinical setting.

Question 8

What are the strengths of case reports and case series?

Answer 8

• Relatively quick
• Inexpensive
• May identify new/ emerging diseases
• May generate hypotheses for analytic studies
• May provides insight into disease mechanisms

Question 9

What is the weakness of case reports and case series?

Answer 9

• No comparison groups
• Small study population (rare/emerging disease)
• Temporal ambiguity

Question 10

What is ecological studies?

Answer 10

Involve aggregated data at the population level and focuses on the comparison of groups.

Question 11

What is the strength of ecological studies?

Answer 11

• Easily conducted
• Inexpensive
• Able to pull different groups for comparison

Question 12

What is the weakness of ecological studies?

Answer 12

• Results can be diffcult to interpret
• Ecological fallacy
• Lack of adequate data
• Temporal ambiguity

Question 13

What is ecological fallacy?

Answer 13

• When aggregated-level results are used to draw conclusions about individual-level relationships.
• Ecological studies assume heterogeneity of exposures.

Question 14

What are cross-sectional studies used for?

Answer 14

Usually used to compare different exposure subpopulations.

Question 15

When and why do we conduct a cross sectional study?

Answer 15

• To gather data on the prevalence of health behaviors, risk factors, and disease presence.
• To learn about a population.
• To help monitor trends over time.

Question 16

What are the strengths for cross-sectional studies?

Answer 16

• Relatively quick with no long periods of follow-up
• Inexpensive
• Multiple outcomes can be researched at one time
• May generate hypotheses for analytic studies
• Long duration and common disease are easily captured

Question 17

What are the weakness of cross-sectional studies?

Answer 17

• Can’t establish causal relationships
• Subject to selection bias
• Subject to non-response bias
• Subject to survival bias
• Short duration disease may be underrepresented

Question 18

When and why do we conduct a case control study?

Answer 18

• To study rare disease
• To study multiple exposures that may have a relationship with a single outcome
• When funding or time to study the disease of interest is limited

Question 19

What is odd ratios?

Answer 19

Identifies that their is a statistical association between a disease and an exposure.

Question 20

Odd ratios

Answer 20

Quantify the probability of and association between a disease/outcome and an exposure.

Question 21

What is selection bias?

Answer 21

Doesn’t fully repersent every group.

Question 22

Recall bias

Answer 22

Differential accuracy of recall between cases and controls.

Question 23

Interview bias

Answer 23

Interview probes cases differently than controls.