ESA 1 POP SCI

Question 1

What is demographic transition?

Answer 1

The transition from high birth and death rates to lower birth and death rates as a country develops from a pre-industrial to an industrialised economic system.

Question 2

What is economic transition?

Answer 2

The changing structure of employment during economic development, moving away from agriculture and increasingly services.

Question 3

What is a consequence of demographic transition?

Answer 3

Ageing and disability due to larger older population with illness and disability

Question 4

How should a sample be chosen?

Answer 4

Should be as representative as possible of the population

Question 5

What is the central limit theorem?

Answer 5

The distributions of means of samples have a similar shape regardless of population. They will distribute symmetrically.

Question 6

What is a 95% confidence interval?

Answer 6

The range that is likely to contain the mean of the values 95% of the time.

Question 7

What does a wider CI indicate?

Answer 7

Greater variation, could be due to small population size

Question 8

What is normal distribution?

Answer 8

The means of the means of samples approximates to the mean of the population values, which distribute to the normal distribution.

Question 9

What is used to estimate precision?

Answer 9

Confidence intervals

Question 10

What types of bias may be present in studies?

Answer 10

Selection bias

Information bias

Question 11

What is the effect of selection bias?

Answer 11

• errors in generalisability, as population not representative.
• errors in compatibility, groups compared are not from same population.

Question 12

What does differential recall error result in and which study design is this most common in?

Answer 12

Information bias

Most common in case-control studies

Question 13

Which studies are prone to observer or interviewer error?

Answer 13

All studies

Question 14

Which studies are vulnerable to measurement error and mis-classification?

Answer 14

All studies

Question 15

How can you respond to confounding?

Answer 15

Direct or indirect standardisation

Question 16

What is a confounder?

Answer 16

An additional variable that has an effect on the dependent variable being measured.

Question 17

How do cohort studies and case-control studies differ?

Answer 17

Cohort study recruits exposed and unexposed groups BEFORE either have any disease.
Case-studies does the reverse and choose groups with the case and control and look back on their exposures.

Question 18

What are the 2 types of cohort study?

Answer 18

Concurrent and prospective

Question 19

What is incident rate ratio?

Answer 19

The ratio of INCIDENCE rates of outcome in groups defined by levels of exposure AT A PARTICULAR TIME.

Question 20

What is an odds ratio?

Answer 20

The ratio of odds outcome in groups defined by levels of exposure at a particular time (no measurement unit)

Question 21

What is a risk ratio?

Answer 21

Ratio of PREVALENCE proportions of outcome in groups defined by levels of exposure at a PARTICULAR TIME.

Question 22

If groups have identical time periods of follow up, how will the incidence ratio ratio and risk ratio change?

Answer 22

They will be the same, as incidence will equal prevalence.

Question 23

What do incidence rate ratio, odds ratio and risk ratio all describe?

Answer 23

The relative risk

Question 24

What 3 factors influence prevalence?

Answer 24

Incidence, number cured and number died

Question 25

What is the calculation used to calculate prevalence?

Answer 25

Incidence x duration of disease

Question 26

What is an example of a descriptive study design?

Answer 26

Cross-sectional survey, analysed to give prevalence

Question 27

Give 2 examples of analytical study designs.

Answer 27

Case control and cohort

Question 28

Which type of study can be analysed by risk ratio, incidence rate ratio AND odds ratio?

Answer 28

Cohort studies

Question 29

Which study design can only be analysed with odds ratio?

Answer 29

Case-control