More Than a Number: A Guide to How Global Health is Measured


SEATTLE — As responses to disease epidemics and the leading causes of mortality become more sophisticated, the way of categorizing how global health is measured undergoes similar innovation and refinements. Health is evaluated using several different indicators — here’s a quick and simple guide to understanding the current units of measurement and key terminology used when describing global health:

Why is Measuring Global Health Important?

Summary measures of global health are used to help assess the overall health of a population which typically take into account disability, mortality and morbidity data. According to the National Center for Biotechnology Information (NCBI), health scores can also reflect perceived quality of life or functional status, including physical functioning and emotional well-being.

Measuring the quality of life, in tandem with summarizing physical well-being, is critical to understanding the prevalence and severity of conditions that cause significant periods of suffering but don’t directly lead to fatalities. Although summarizing human experience using numbers may seem impersonal, summary statistics of global health trends are vital to improving the living conditions of those residing in both developing and developed countries.

The “ALYs”: Three Key Units of Measurement

  • HALY: Health-adjusted life year

HALYs are an umbrella term for a family of measures including disability-adjusted life years (DALYs) and quality-adjusted life years (QALYs), according to Annual Review. HALYs simultaneously describe morbidity and mortality rates with a single number and are useful for estimating the burden of disease and comparing the impact of specific health conditions on communities.

  • DALY: Disability-adjusted life year

One DALY can be thought of as one lost year of “healthy” life, according to the World Health Organization (WHO). DALY measurements can be used to compare the overall health and life expectancy of various countries.

The sum of the DALYs derived from a given population is a measurement of the gap between the population’s current health score and the ideal health score they are striving for.

DALYs for a health condition or disease are calculated by adding the years of life lost due to premature mortality and the years lost due to disability for people living with a specific disease or health condition.

  • QALY: Quality-adjusted life year

QALYs are used as a measure of disease burden that accounts for both the health-related quality of life an individual is predicted to experience and length of life expectancy.

A QALY score is valued on a scale where the value of being dead is 0 and perfect health is set to a value of 1. It’s possible for a population to have a negative QALY score, meaning that states worse than dead can exist, according to Value in Health.

The QALY score also helps to track the effectiveness of medical intervention on increasing life expectancy of a particular health condition. This popular conceptual tool can lead to improved decision-making in the global health field. Assessing which diseases and health conditions contribute to alarmingly low QALY’s help to prioritize treatment and improve health services.

DALY Criticism and Problems with Quantifying Global Health

While the DALY is revered by some as a revolutionary analytical tool for quantifying global health, critics of DALY measurements believe that the conceptual and technical basis for DALYs is flawed.

According to researchers at the University of Ljubljana, the DALY measure has mostly been criticized due to its four built-in social preferences: different weights for sexes, different age weights, discounting future years lost and severity weighting of disabilities.

Sudhir Anand and Kara Hanson, two economists who published a critical review of DALYs in the Journal of Health Economics in 1999, argue that DALYs are calculating both the burden of disease and the burden of underdevelopment in developing countries.

Since DALYs are based on baseline measurements from wealthy countries, the differential found between developing and developed populations leads Anand and Hanson to believe that the DALY fails to account for differences in resources, according to the Journal of Global Health.

Additionally, in complex measures like DALY and QALY the concept of measuring quality of life remains vaguely defined. Since these units of measurements are globally utilized, it’s daunting and near impossible to consolidate the differing perspectives of various cultures into one definition of a high-quality life.

Improving How Global Health is Measured

Although there may be flaws in the way global health is currently measured, WHO, along with the World Bank and USAID, are dedicated to improving health data through measurement improvements and the encouragement for accountability among global health leaders.

One of the major obstacles to improving global health data is the lack of a coordinated approach between developing and developed nations on what information countries should collect to measure progress in health, according to WHO.

To overcome this obstacle, global health leaders are endorsing a Roadmap for Health Measurement and Accountability in conjunction with a five-point Call to Action. A shared approach that nations and development partners can use to prioritize research and measure global health are outlined within the Roadmap while the Call to Action proposes measurable targets to guide the Roadmap’s process.

Targets within the Call to Action include equipping at least 80 percent of health facilities with electronic systems for real-time reporting of health statistics by 2025 and ensuring that all hospitals use the WHO standard ICD (International Classification of Disease) to report the cause of every death.

With this current plan in action, accurate measurements of global health will soon pave the way for improved health services worldwide.

Daniela Sarabia

Photo: Flickr


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