Evidence for Population Health

Question 1

What is anecdotal evidence?

Answer 1

evidence that comes from a patient themselves

describes their story and experience

Question 2

What are the pros of anecdotal evidence?

Answer 2

quick
easy to perform in clinic
new conditions can be discovered
provides new potential risk factors

Question 3

What are the cons of anecdotal evidence?

Answer 3

not scientific
affected by observer bias
difficult to conclude disease cause

Question 4

What is cross sectional surveying?

Answer 4

observational study analysis of data collected from a population at one specific point in time

Question 5

What are the pros of cross sectional surveying?

Answer 5

quick

good at estimating prevelance

Question 6

What are the cons of cross sectional surveying?

Answer 6

only represents that point in time
cannot estimate incidence
may lead to bias

Question 7

What is the incidence of a disease?

Answer 7

number of new cases in a given time

Question 8

What is the prevalence of a disease?

Answer 8

number of cases of a disease that are present in a particular population at a given time

Question 9

What is a common tool used to measure incidence?

Answer 9

a register

Question 10

What is the counterfactual method?

Answer 10

predicting what would happen if…
would the disease have happened:
at the same time in the same person?
anyway if the factor was not present?

Question 11

What are ecological studies?

Answer 11

observe a group

studies of risk-modifying factors based on populations defined either geographically or temporall

Question 12

What are the pros of ecological studies?

Answer 12

cheaper
less prone to bias due to participation
easy to perform
provides new hypothesis about the cause of a disease/risk factors

Question 13

What are the cons of ecological studies?

Answer 13

Ecological fallacy - conclusions about individuals based only on analyses of group data
Assume average value of the risk factor/incidence to all individuals
data collection may vary

Question 14

What is a case-controlled study?

Answer 14

compares patients who have a disease (cases) with patients who do not have the disease (controls)

Question 15

What are the pros of case control studies?

Answer 15

good for rare diseases/exposures

quick follow up

Question 16

What are the cons of case control studies?

Answer 16

prone to selection/participation bias
finding a suitable control group can be difficult
difference in recall = bias

Question 17

What is a cohort study?

Answer 17

passive follow-up of a group of people who share common experiences/conditions for the outcome

Question 18

What are the pros of cohort studies?

Answer 18

good for rare exposures
can look at multiple outcomes
reduces information bias
direct measurement of incidence

Question 19

What are the cons of cohort studies?

Answer 19

not useful for rare diseases
expensive
long

Question 20

What is error in research?

Answer 20

the difference between an estimated value and true value

Question 21

What is the definition of bias?

Answer 21

systematic, non random deviation of results and inferences from the truth
process leading to deviation

Question 22

What is diagnostic bias?

Answer 22

when diagnosis is based only on exposure

Question 23

What is self selection bias?

Answer 23

Can happen when:
participants contact the study - more likely to participate if FH
‘healthy worker effect’ - workers self selecting more likely to be healthier

Question 24

What are the types of information bias?

Answer 24

Recall bias
Interviewer bias
Surrogate bias
and more…

Question 25

What is misclassification bias?

Answer 25

occurs when data is placed into categories - can be put in the wrong categories

Question 26

What is intention to treat?

Answer 26

A method of analysis for randomized trials in which all patients randomly assigned to one of the treatments are analysed together, regardless of whether or not they completed or received that treatment

Question 27

What is randomised controlled trials?

Answer 27

AKA clinical trail
Random control and treatment group
Give treatment group intervention
Look at outcome

Question 28

What are the pros of randomised controlled trials?

Answer 28

Strongest evidence for casuality
Selection bias/confoundering removed
Decreased observer bias

Question 29

What are the cons of randomised controlled trials?

Answer 29

Not real life
High cost
Most of the time it is too inappropriate/unethical