lect 3- week1 causality

Question 1

what is causality?

Answer 1

relationship between cause and effect, where one event (the cause) brings about another effect ( the effect)

Question 2

what is the difference between association and causation?

Answer 2

• association is simply an identifiable relationship between an exposure and disease
• causation: implies that there is a true mechanism that leads from exposure to disease

Question 2

two step process to carry out studies and evaluate evidence?

Answer 2

1. determine if an association is present
2. if an association is demonstrated, determine whether the observed association is likely to be a causal one

Question 2

what are the bradford- hill criteria?

Answer 2

strength, consistency, specificity, temporality, biolgical gradient, plauability, coherence, experimental

Question 3

name the 4 types of causal factors

Answer 3

• Necessary and sufficient
• Necessary, but not sufficient
• Sufficient, but not necessary
• Neither sufficient, nor necessary

Question 3

threats to validity?

Answer 3

• confounding
• bias
• chance

Question 4

What is an essential criterion for establishing causality?

Answer 4

Temporal precedence is an essential criterion for establishing causality, meaning the exposure must precede the disease.

Question 5

what methods prevents confounding?

Answer 5

matching
randomisation
restriction

Question 6

what is confounding?

Answer 6

A confounding variable is any prognostic factor or effective
treatment that is not equal in the groups being compared

Question 6

what is bias?

Answer 6

any systematic error in an epidemiological study that results in an
incorrect estimate of the association between exposure and risk of disease.
* Many different types of bias occur. Two common biases are:
* Selection bias
* Measurement bias

Question 6

what is chance?

Answer 6

Inevitably, because studies cannot include entire populations
and continue indefinitely in time, some chance factor may
result in study outcomes not representing the ultimate true
values, even if bias and confounding are non-existent.

Question 7

What is selection bias in a study?

Answer 7

Selection bias occurs when there is a systematic difference between the characteristics of the people selected for a study and those who are not.

Question 8

What is recall bias in a research study?

Answer 8

Recall bias occurs when study participants have difficulty recalling information accurately, leading to biased data.

Question 8

What is confounding in a research study?

Answer 8

onfounding arises when an extraneous variable affects both the dependent and independent variables, leading to a spurious association.

Question 9

How can confounding be addressed in a research study?

Answer 9

onfounding can be addressed by using statistical techniques such as multivariate analysis or stratification

Question 10

Does smoking cause lung cancer?

Answer 10

Smoking is strongly associated with lung cancer, with consistent results across many studies. There is a dose-response relationship, and smoking precedes the diagnosis of cancer. Though the exact mechanism is not fully understood, the coherence of data and successful interventions (like smoking cessation) support causation.

Question 11

What are some examples of association that do not imply causation?

Answer 11

Hospital stays are associated with increased mortality rates, but this does not mean hospitalization causes death.

Question 12

how can researchers account for the role of chance in their studies?

Answer 12

Researchers can account for the role of chance by increasing the sample size to minimize the effects of chance.