Health information Flashcards
Census definition
Snapshot enumeration survey
Most complete set of population data available
allows for- making comparisons between regions, resource allocation, analysing trends, denominator for health/population statistics.
ONS is responsible for the census in England.
Census data
Household questions: Type, owner/rented, number of rooms, type of heating etc
Number of vehicles
Household members
Individual questions
Demographics
Migration
Health
Education level
Limitations to national census
- Cost
- Under enumeration: particular groups are hard to reach e.g inner city men, HMOs, non english speakers, extremes of age, military personnel, people experiencing homeless, traveler communities.
- Timeliness
- Misreporting: self reporting of data
Alternatives to census
- Rolling census
- Population projections
- Population registers: ongoing collection of data on individuals. More up to date, and good databases allow for stat analysis. However, not a single snapshot so harder to compare regions, risk on confidentiality breaches.
Routine data
Data collected routinely e.g birth and death registries
Uses: Assess burden, compare location or time, Health service assessment, research and evaluation.
+ Readily available
+ Cheap
+ Some data points very robust
+ Large numbers
+ Data sources can be linked
+ Baseline data
- Limited to what’s been collected (not a perfect representation for your question)
- Variable quality e.g poor ethnicity coding
- Access may be limited
- Delayed publication
- May be incomplete
- Often poorly presented and analysed, difference in ways completed.
Ad hoc data
Data collected for a specific purpose.
+ Specify what you need
+ Target a subgroup
+ Responsive to emerging need
+ Quality can be managed
+ Can define collection technique
+ Greater depth of stat analysis
- Costly
- May be hard to link to routine sources
- Smaller sample
- Selection bias
- Validity/reliability may be poor
Define Demography
The study of characteristics and dynamics of human populations
Key demographic factors
Population size, Age structure, Fertility, Mortality, Survival.
Fertility rate calc
no of live offspring per 1000 per year in fertile women (15-49)
Mortality calc
No died per year x length of age band
/
total individuals in age band
Describe UK gender differences
More boys age 0-4 due to higher male birth rate.
Overall more females than males due to greater male mortality from accidents and suicide (younger) then generally longer female life expectancy.
Methods for population estimates
Cohort Component method
Special group calculations
Projections
Cohort component method
Technique for mod year population estimates
- take prev mid year estimate
- Increase age by 1 year
- Add births - ONS
- Subtract deaths - ONS
- Adjust for external migration - International passenger survey
- Adjust for internal migration - GP registration
- Quality control checks
Factors that affect projections
Birth sex ratio- 1.05 males
Mortality- extrapolate historical trends
Fertility and Migrations- hard to predict. Now incorporating probabilities of random changes (outwit trends) reported as probabilistic population forecasting (with 95% CI)
Life tables
list the probability a person will die before their next birthday based on age and sex.
Estimated by ONS
Period life tables
Calculated using age specific mortality in a given year.
Shows life expectancy if a given age in a given year had that years mortality rate applied for their whole life.
Life tables for specific years are generally period life tables.
Cohort life tables
Age specific mortality rates including projections. Showing an adjusted life expectancy based on projected mortality.
Can be used in survival analysis
Applications of life tables
Proportion of people born in different years who are still alive.
Remaining life expectancy
Probability of surviving to a set age
Life expectancy can derive DALY, HALE, PYLL
Replacement fertility
The number of children each women needs to have (on average) in order to maintain the current population.
UK approx 1.7
Generally 2.1 in developed countries
Higher in global south (3.45) due to high mortality rates.
Even if this drops the effect would not ben seen quickly depending on age profile of population, changes in age mortality rates, and childbearing postponement
Factors that affect population structure
Fertility, mortality, migration,
population time bomb