3 - Study designs (part I): Observational epidemiological studies

Question 1

What is a target population?

Answer 1

the whole group you want to study

Question 2

What is a study population?

Answer 2

one where you can legitimately apply your conclusions of the study

Question 3

systematic sampling

Answer 3

Every nth item in the target population is selected

• Not useful if there is a pattern in your list

Question 4

stratified sampling

Answer 4

• Divide population into sub-groups and and take sample from there

Question 5

census

Answer 5

all the population

Question 6

sample

Answer 6

fraction of the population

Question 7

types of non-probabilistic sampling

Answer 7

• convenience
• purposive
• quota
• snowball

Question 8

types of probabilistic sampling

Answer 8

• simple random
• systematic
• stratified
• complex

Question 9

experimental study

Answer 9

investigator controls which subjects receive the treatment/ exposure under consideration

Question 10

observational study

Answer 10

investigator does not control which subjects receive treatment/ exposure under consideration

Question 11

types of observational studies

Answer 11

descriptive and analytical

Question 12

what are the types of descriptive study

Answer 12

• case report

- case series

Question 13

what is a case report

Answer 13

• individual based measurements

- prevalence studies

Question 14

What is a case series?

Answer 14

A written report on the details of a cluster of related cases

Question 15

what are the types of analytical study?

Answer 15

• case-control
• cohort
• cross sectional
• ecological study
• systemic review
• meta-analysis

Question 16

what are the reasons for carrying out an observational study?

Answer 16

• cheap
• quick
• ethical reasons
• wide range of diseases can be investigated

Question 17

cross-sectional study

Answer 17

A study in which a representative cross section of the population is tested or surveyed at one specific time.

Question 18

Case-control study

Answer 18

• used to identify factors that may contribute to a medical condition
• compares a group of patients who have that condition with a group of patients who do not.

Question 19

cohort study

Answer 19

a group of exposed individuals (individuals who have been exposed to the potential risk factor) and a group of non-exposed individuals are followed over time to determine the incidence of disease

Question 20

case-control study vs cohort study

Answer 20

Case-control - Retrospective only, (Looking for risk factor exposure in pts with known outcomes)
Cohort - can be prospective or retrospective (Looking for outcomes in patients with predefined exposure to risk factor or disease state)

Question 21

Nested case-control study

Answer 21

• case control-study

- cases and controls are drawn from the population in a cohort study

Question 22

family studies

Answer 22

Scientific studies in which researchers assess hereditary influence by examining blood relatives to see how much they resemble each other on a specific trait.

Question 23

ecological studies

Answer 23

Studies that examine mean outcome and mean exposure at an area (and population) level

• however association does not mean causation

Question 24

systematic review

Answer 24

• review of a clearly formulated question
• uses explicit, systematic methods
• identify, select, and critically appraise relevant research,

Question 25

meta-analysis

Answer 25

a procedure for statistically combining the results of many different research studies