Why historical health data falls short in predicting future health care needs

The average 65-year-old in 2025 has very different health needs compared to a 65-year-old in 1950.

Yet governments often still use historical, age-based and gender-specific profiles to predict how we will use health services at every stage throughout our lives.

This approach, based on invalid assumptions, explains why supply and demand for healthcare can be so out of whack – and why the disparity could be even worse for the 65-year-olds of the future.

A flawed method

Relying on current or past use of health services by age group and gender to project onto future population estimates is fundamentally flawed.

It assumes health care needs remain constant, but in reality they evolve over time due to a range of factors including changes in diet, environment and technology.

These influences can affect individuals differently depending on when they were born - their ‘birth cohort’ – particularly if they occurred during critical developmental periods.

As a result, people born in different years may have different health over their lifetime.

Current methods assume these people have the same health.

 For example, teenagers today have more access to highly processed foods compared to teens from previous generations, which can result in very different health outcomes.

Not accounting for changes across birth cohorts means future health service needs can be either vastly over or under-estimated.

A new approach

My colleagues and I conducted a study into health needs by age and gender across birth cohorts in Australia, using data from the Household, Income and Labour Dynamics in Australia (HILDA) Survey which has been conducted annually since 2001.

We found differences between earlier and more recently born cohorts in terms of prevalence of health conditions:

• A higher likelihood of probable mental disorders across successive birth cohorts for both genders, but especially women.
• A higher likelihood of long-term health conditions among more recently born women
• A decline in the likelihood of physical health problems across cohorts for both men and women.
• Stabilised overall rates of long-term health conditions for men, despite the increase in mental health problems.

We conclude that traditional planning models may lead to inaccurate estimates of future health care needs.

Incorporating cohort effects shows current planning may fall well short of demand for mental health needs but are overestimated for physical health problems.

The way forward

Unless governments and health care planning shifts away from a historical approach and move to include cohort-specific changes, they risk under - or overestimating health service requirements for the future.

It's critical we make the most effective use of available and future health care resources, and plan for recruiting and training health care professionals to meet the needs of the generations to come.

The research paper was published in The European Journal of Health Economics.

Collaboration and acknowledgements