Taxonomic Axes

Question 1

Counterfactual definition of effect

Answer 1

The outcome that an individual would have experienced if they had received a particular treatment or exposure compared to the outcome that an individual would have experienced if they had not received that treatment or exposure

Question 2

Problem of counterfactual definition of effect

Answer 2

One of these 2 is impossible (it is contrary to the facts; it won’t happen - which is why it is a theoretical definition of effect; you either receive the treatment or you don’t)

In the real world we have association and measure of association

Question 3

Classification of study designs according to the intention

Answer 3

Descriptive
Analytic

Question 4

Classification of study designs according to the assignment of exposure

Answer 4

Experimental
Observational

Question 5

Classification of study designs according to the follow up

Answer 5

Longitudinal
Cross-sectional / transversal

Question 6

Classification of study designs according to the direction of analysis

Answer 6

Cohort
Case control

Question 7

Classification of study designs according to the beginning of the study

Answer 7

Prospective
Retrospective

Question 8

Classification of study designs according to the measurement

Answer 8

Individual
Population

Question 9

Descriptive studies

Answer 9

Reason: purely descriptive

Doesn’t look for a cause/effect relationship (just describes)

Question 10

Analytical studies

Answer 10

Reason: ethiological

Explore cause-effect relationship

Question 11

Observational studies

Answer 11

Exposed/non-exposed people and you observe what happens

Question 12

Experimental studies

Answer 12

You decide who is exposed and who isn’t —› you create the samples

Question 13

Longitudinal studies

Answer 13

Follow up

Question 14

Transversal / cross-sectional studies

Answer 14

No follow up

Harder to establish cause-effect (we don’t know if the exposure was before or after the outcome)

Question 15

Cohort study

Answer 15

1º thing we do is look for exposure (smokers and non smokers)

Question 16

Case control study

Answer 16

1º look for the outcome

(people with/without cancer and ask them if they smoke have smoked)

Question 17

Prospective studies

Answer 17

Incident cases (outcome after the starting of the study)

(Longitudinal)

Question 18

Retrospective studies

Answer 18

Prevalent cases (outcomes have already occurred)

(Longitudinal)

Question 19

Individual measurement

Answer 19

Each person is classified in the study by exposure/disease status

Question 20

Population measurement

Answer 20

Averages - measured in groups

Correlational / ecological studies (we don’t know if this is cause-effect)