Health status indicators: incidence, prevalence, DALY, HALE, mortality and self-assessed health (VCE HHD Unit 3 AoS 1)

What this dot point is asking

The 2025 study design lists the indicators explicitly: incidence, prevalence, morbidity, burden of disease, DALY, YLL, YLD, life expectancy, HALE, mortality (maternal, infant and under five) and self-assessed health status. The key skills are to "interpret and apply indicators used to measure health status" and to "use data to evaluate the health status of Australians".

In the exam this dot point appears in three forms:

1. Define or describe an indicator (1 to 2 marks). The command term matters: "describe mortality" needs more than "death".
2. Apply an indicator: explain how a risk factor or program increases or decreases it (2 to 4 marks).
3. Interpret data: read a graph or table, quote figures with the correct unit, and draw a conclusion (2 to 6 marks, and often part of the Section B extended response).

Definitions examiners accept

Health status

Health status is an individual's or a population's overall level of health, taking into account aspects such as life expectancy, amount of disability and levels of disease. It is objective and measured, unlike health and wellbeing, which is subjective (see concepts and dimensions of health). Self-assessed health status is the exception: it is a measured indicator of a subjective judgement.

Incidence and prevalence

• Incidence: the number or rate of new cases of a disease or condition in a population during a given period.
• Prevalence: the number or proportion of cases (new and existing) of a disease or condition present in a population at a given time.

The relationship between them depends on how long people live with the condition. Influenza has high incidence each winter but lower prevalence at any moment because people recover within days. Arthritis, asthma and type 2 diabetes have high prevalence because people live with them for years. In the ABS National Health Survey 2022, 49.9 per cent of Australians had at least one chronic condition, with mental and behavioural conditions (26.1 per cent), back problems (15.7 per cent) and arthritis (14.5 per cent) the most common. Those are prevalence figures.

Morbidity and mortality

• Morbidity refers to ill health in an individual and levels of ill health in a population, often expressed through incidence or prevalence.
• Mortality refers to death, often at a population level, usually expressed as a rate (deaths per 1,000 or per 100,000 population).

The study design names three specific mortality indicators:

These three indicators are sensitive to the prerequisites for health: safe water, sanitation, nutrition, education and access to skilled health care. That is why they appear so often in Unit 4 comparisons of low-, middle- and high-income countries.

Life expectancy and HALE

• Life expectancy: the average number of years a person of a given age and sex can expect to live if current death rates do not change. It is usually quoted at birth.
• Health-adjusted life expectancy (HALE): the average number of years a person can expect to live in full health, without disease or injury.

The gap between the two is the number of years expected to be lived in ill health.

Note that the AIHW's HALE estimates use AIHW-derived life tables for 2024, so its implied life expectancy (81.6 males, 85.5 females) differs slightly from the ABS three-year figure. When a question gives you a figure, use the one provided and quote its source and year.

Burden of disease, DALY, YLL and YLD

• Burden of disease is a measure of the impact of diseases and injuries on a population. It combines the years of healthy life lost to living with ill health (non-fatal burden) with the years of life lost to dying prematurely (fatal burden).
• DALY (disability-adjusted life year) is the unit: one DALY is one year of healthy life lost.
• YLL (years of life lost) measures fatal burden: years lost because people died before the ideal life expectancy.
• YLD (years lived with disability) measures non-fatal burden: healthy years lost because people lived with illness, injury or disability.

Burden of disease is powerful because it puts conditions that kill (such as lung cancer, mostly YLL) and conditions that disable (such as back pain, almost all YLD) on the same scale. A condition can rank high in burden without ranking high as a cause of death. In 2024, for example, dementia was the leading cause of death (9.4 per cent of deaths, ABS), while back pain, which rarely causes death, was the third leading cause of burden.

Self-assessed health status

Self-assessed health status is an individual's own rating of their health, usually on a scale of excellent, very good, good, fair or poor, collected through surveys such as the ABS National Health Survey. In the 2017-18 National Health Survey, 56.4 per cent of Australians aged 15 and over rated their health as excellent or very good and 14.7 per cent as fair or poor. It is subjective, so it captures how people feel about their health across all dimensions, including conditions that do not appear in mortality data, but it is influenced by expectations, culture and comparison with others.

Strengths and limitations of each indicator

Examiners sometimes ask why a particular indicator is useful or what it misses. Have one strength and one limitation ready for each.

Applying indicators: the direction rule

The 2024 and 2025 examiners' reports both penalised answers that said a factor "impacts" or "affects" an indicator without saying which way. Always state the direction and the condition:

• Not "smoking affects mortality" but "smoking increases mortality from lung cancer".
• Not "obesity impacts life expectancy" but "obesity decreases life expectancy by increasing mortality from cardiovascular disease and type 2 diabetes".
• Not "vaccination improves morbidity" but "vaccination decreases the incidence of measles".

Reading health data in the exam

• Quote the unit. Rates are per 1,000 or per 100,000; burden is in DALY or DALY per 1,000; life expectancy in years; proportions in per cent. The VCAA FAQ gives the example of under-five mortality being a rate per 1,000 live births, not a number of deaths.
• Name both groups and the direction when comparing: "Group B had approximately 60 per cent rating their health as excellent or very good, compared with approximately 40 per cent of group A" (the style of the 2025 high-scoring response).
• Distinguish age-standardised from crude rates. Age-standardised rates remove the effect of population ageing, so they are the right basis for comparing across time or between groups with different age structures. Dementia ranked 5th for burden on an age-standardised basis but 2nd by crude numbers in 2024, showing the effect of an ageing population.
• Describe a trend with start and end points: "The death rate from cardiovascular disease rose to a peak of about X per 100,000 in the late 1960s and then fell steadily to about Y by 2019."

Linking indicators to the rest of Unit 3

Indicators are the evidence base for everything else in Unit 3. You use them to describe variations in health status between population groups, to explain the contribution of smoking, vaping and alcohol and overweight, obesity and nutritional imbalance to Australia's health status, and in Unit 3 AoS 2 to show how old public health, the biomedical approach and the Ottawa Charter improved health status since 1900. A top-band answer anywhere in the course names the indicator, states the direction of change and, where possible, supports it with a dated figure.