Flashcards Key Concepts in Population Health and Demography

WHO definition of health (1946)

"A state of complete physical, mental and social well-being and not merely the absence of disease or infirmity."

Bircher definition of health (2005)

"A dynamic state of well-being characterized by an individual's physical, mental and social potential to meet the demands of life unique to the individual's age, culture and personal responsibility."

Dependency ratio

(Population aged 0-14 + population 65+) ÷ population aged 15-64

Healthy life expectancy (HALE)

Expected number of years lived in good health

Excess deaths

Actual deaths − expected deaths (expected = the pre-event trend)

Intrinsic capacity

The sum of a person's physical and mental capacities

Functional ability

Intrinsic capacity + environment, which together let a person be and do what they value

Non-communicable diseases (NCDs)

Chronic diseases such as heart disease and cancer: 75% of deaths in 2023 (51% in 1980)

Sustainable Development Goals (SDGs)

The UN's 17 goals and 169 targets, with a target year of 2030

Social determinants of health (CSDH) framework

WHO (Solar & Irwin) chain: context → structural determinants (position) → intermediary determinants (daily conditions) → health equity

Structural determinants

Factors that set socioeconomic position: class, income, education, occupation, gender, race. The "causes of the causes."

Intermediary determinants

Material circumstances, behaviors and biology, psychosocial factors, and the health system

Demography

The scientific study of the size, composition, and distribution of populations and their changes through fertility, mortality, and migration

Balancing equation

N(T) = N(0) + Births − Deaths + In-migrants − Out-migrants

Natural increase

Births − deaths

Net international migration

Immigrants − emigrants (in-migrants − out-migrants)

Demographic rate

Number of events ÷ person-years of exposure

Person-years

The sum of the time each person was in the population at risk. Usually estimated by the mid-year population.

Crude birth rate / crude death rate

Births (or deaths) ÷ person-years, usually per 1,000

Crude growth rate (CGR)

CBR − CDR + crude in-migration rate − crude out-migration rate (US 2024-25 ≈ 0.52%)

Mean annualized growth rate

ln(N(T)/N(0)) ÷ T. Equals the CGR when the instantaneous growth rate is constant.

NCHS

National Center for Health Statistics: counts US births and deaths (the Census Bureau counts population and migration)

Age-specific death rate (ₙMₓ)

Deaths ÷ person-years for people aged x to x+n

Crude death rate as a weighted average

CDR = Σ Cᵢ × Mᵢ (Cᵢ = age-group share of the population, Mᵢ = age-specific rate). The shares sum to 1.

Age standardization

Applying one standard age structure to each population's age-specific rates to remove the effect of age composition

Cohort

The aggregate of all units that experience a particular demographic event during a specific time interval

Period measure

A measure built from one time period's rates (life expectancy, TFR)

Life expectancy at age x

The number of additional years a survivor to age x will live at current mortality rates

Infant mortality rate (IMR)

Deaths under age 1 in a year ÷ live births that year × 1,000

Neonatal mortality

Deaths in the first 28 days of life

Postneonatal mortality

Deaths from day 29 to 365

Child mortality rate

Probability of dying before age 5, per 1,000 live births (under-5 mortality)

Fetal mortality rate

Stillbirths (20+ weeks) ÷ (live births + stillbirths)

Maternal mortality ratio

Deaths from pregnancy, childbirth, or the postpartum period ÷ live births (often per 100,000)

Underlying cause of death

The disease or injury that initiated the chain of events leading to death

Total fertility rate (TFR)

Average number of children a woman would have at current age-specific fertility rates

Replacement fertility

A TFR of about 2.1

Organic data

Data produced by automatic tracking: social media, traffic cameras, scanners, smartwatches

Administrative data

Data from government record keeping: registration, transactions, records

Designed data

Censuses and surveys. The questions have a pre-specified purpose.

Census vs. survey

A census counts everyone. A survey asks a sample to describe the larger population.

Inference

Using information obtained imperfectly to describe a larger, more abstract entity

Consumer Price Index (CPI)

Average change over time in prices paid for a representative basket of goods and services

Validity

Whether the measure captures the construct (the correlation between the measure and the true value)

Measurement error

The gap between the true value and the response given

Coverage error

The gap between the target population and the sampling frame

Sampling error

The gap between the sampling frame and the sample

Nonresponse error

The gap between the sample and the respondents

Response bias

Measurement errors in a consistent direction

Response variance

Measurement errors in random directions

Four cognitive steps

Comprehension → retrieval → judgment (estimation) → reporting

Biomarkers

Objective biological measures in surveys (blood pressure, hemoglobin, dried blood spots)

Randomized controlled trial (RCT)

A study in which the researcher randomly assigns subjects to treatment or control

Observational study

A study in which subjects choose their own exposure and researchers observe

Natural experiment

An observational study where assignment to treatment is "as if randomized by nature"

Confounder / confounding

A third factor linked to both the exposure and the outcome

Random assignment

Assignment by chance, so the groups are balanced on everything except treatment

Balance table

A table comparing treatment and control groups at baseline to show they were similar

Intent to treat

Comparing everyone assigned to treatment with controls, regardless of uptake. This preserves randomization.

Analysis by treatment received

Comparing those who actually took the treatment with others, which is biased

Placebo

A look-alike inactive treatment given to controls

Blinding / double blind

Subjects don't know their group / researchers don't know either

Attrition

Loss of participants over the course of a study

Inverse probability weighting

A post-survey adjustment for non-random attrition

Compliance

The share who actually take the assigned treatment

Difference-in-differences

(Treatment change over time) − (control change over time)

Triple difference

The difference between the DiD for one subgroup and the DiD for another

Social gradient

Health improves step by step with every rise in social position

Differential exposure / vulnerability / consequences

Lower positions face more hazards, are harmed more by them, and suffer worse economic and social effects of illness (Diderichsen)

Social selection (health selection)

Health determines social and economic position

Social causation

Social position determines health

Life course perspective

Social determinants act across life phases, with immediate and long-term effects

Critical period

A sensitive window when exposure has lasting effects (biological programming)

Accumulation of risk

Harmful exposures add up over the life course

Adverse childhood experiences (ACEs)

Early-life adversities with lasting health effects

Subjective social status

A person's perceived rank relative to others

Official Poverty Measure

3 × the cost of a minimum food diet in 1963, compared with pre-tax cash income

Supplemental Poverty Measure

Counts noncash benefits and taxes, and adjusts for housing costs and geography

Extreme poverty

Living on less than $2.17 per day (2017 PPP)

Purchasing power parity (PPP)

Adjusting income for price differences across countries

Internalising symptoms

Depression and anxiety

Stunting

Height-for-age more than 2 standard deviations below the median

Height-for-age z-score (HAZ)

A child's height compared with a reference population, in SD units. Higher is better.

Conditional / unconditional cash transfer

Money given with strings attached / with no strings

Cluster randomized trial

An RCT that randomizes groups (villages) instead of individuals

First 1,000 days

Conception to the 2nd birthday

Program fidelity

Whether a program was delivered as designed

Health inequity

A difference in health that is unfair and avoidable

Sex

Biological status: chromosomes, gonads, hormones, internal organs, external genitals

Gender

Culturally defined roles, responsibilities, attributes, and entitlements, plus the power relations between men and women

Gender norms

Rules about which behaviors are valued and acceptable for men and women. Restrictive norms prop up power hierarchies.

Androgynous

High on both masculinity and femininity (Bem: two independent scales)

Sex ratio at birth

Boys born per 100 girls, normally about 105

NEET

Not in Education, Employment, or Training

Gender Inequality Index

UN index: parliament seats, secondary education, labor force participation, maternal mortality, adolescent birth rate

Pharmacokinetics / pharmacodynamics

How the body processes a drug / how the drug affects the body

Intersectionality

Overlapping axes of power: race, class, age, ability, gender

Racism

An organized system that ranks "races" by an ideology of inferiority and uses power to allocate resources unequally (Williams)

Structural / institutional racism

Racism embedded in laws, policies, and institutional practices

Cultural racism

The ideology of inferiority embedded in values, language, imagery, and symbols