ESA 1 POP SCI Flashcards
What is demographic transition?
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.
What is economic transition?
The changing structure of employment during economic development, moving away from agriculture and increasingly services.
What is a consequence of demographic transition?
Ageing and disability due to larger older population with illness and disability
How should a sample be chosen?
Should be as representative as possible of the population
What is the central limit theorem?
The distributions of means of samples have a similar shape regardless of population. They will distribute symmetrically.
What is a 95% confidence interval?
The range that is likely to contain the mean of the values 95% of the time.
What does a wider CI indicate?
Greater variation, could be due to small population size
What is normal distribution?
The means of the means of samples approximates to the mean of the population values, which distribute to the normal distribution.
What is used to estimate precision?
Confidence intervals
What types of bias may be present in studies?
Selection bias
Information bias
What is the effect of selection bias?
- errors in generalisability, as population not representative.
- errors in compatibility, groups compared are not from same population.
What does differential recall error result in and which study design is this most common in?
Information bias
Most common in case-control studies
Which studies are prone to observer or interviewer error?
All studies
Which studies are vulnerable to measurement error and mis-classification?
All studies
How can you respond to confounding?
Direct or indirect standardisation
What is a confounder?
An additional variable that has an effect on the dependent variable being measured.
How do cohort studies and case-control studies differ?
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.
What are the 2 types of cohort study?
Concurrent and prospective
What is incident rate ratio?
The ratio of INCIDENCE rates of outcome in groups defined by levels of exposure AT A PARTICULAR TIME.
What is an odds ratio?
The ratio of odds outcome in groups defined by levels of exposure at a particular time (no measurement unit)
What is a risk ratio?
Ratio of PREVALENCE proportions of outcome in groups defined by levels of exposure at a PARTICULAR TIME.
If groups have identical time periods of follow up, how will the incidence ratio ratio and risk ratio change?
They will be the same, as incidence will equal prevalence.
What do incidence rate ratio, odds ratio and risk ratio all describe?
The relative risk
What 3 factors influence prevalence?
Incidence, number cured and number died
