Introduction
Health is a universal human right, and health inequality monitoring is integral to its attainment.
Over the past two decades, there have been remarkable improvements to human health around the world. Globally, life expectancy increased by more than six years between 2000 and 2019 (before the start of the COVID-19 pandemic1), from 66.8 years to 73.1 years (1). Over this period, the burden of disease due to communicable diseases such as HIV and diarrhoeal diseases dropped by over 50% (2). Encouragingly, the proportion of the population that is not covered by essential health services decreased by about 15% between 2000 and 2021 – an impressive pace of progress in expanding universal health coverage, especially before 2015 (3).
Overall measures, however, can mask notable differences between and within populations. For example, in 2019 there was a gap in life expectancy of more than 30 years between the countries with the highest and lowest life expectancies (84.5 years in Japan and 51.8 years in Lesotho, respectively) (1). The burden of HIV and diarrhoeal diseases was concentrated in lower-income countries (2) and among socially disadvantaged populations (4, 5). In many countries, progress towards universal health coverage had stagnated – with only minimal increases in coverage after 20152 – and remained challenged by inequalities (3). For example, within low- and middle-income countries, reproductive, maternal, newborn and child health service coverage was lower among people with lower economic status and education levels compared with people with higher economic status and education levels, and lower in rural areas than in urban areas. People living in poorer households, rural areas and households with older family members (aged 60 years and over) were more likely to experience poverty due to out-of-pocket health spending (3).
Health inequalities are a formidable challenge in the face of new health threats such as COVID-19, and they impede progress in aspects of health that are persisting or worsening, such as many noncommunicable diseases. For example, people from socially disadvantaged populations were less likely to receive a COVID-19 vaccination in 2021 (6) or to access early screening and vaccination for cervical cancer in 2020 (7) – low-cost interventions that save lives.
Looking ahead, substantial opportunities for further global improvements in health lie in understanding and addressing health inequalities – observable differences in health between advantaged and disadvantaged populations. This requires characterizing with better granularity and precision how health and health determinants are experienced across and within populations. This evidence can be used to inform changes that are oriented towards advancing health equity – the absence of unfair, avoidable or remediable differences in health among populations (8).
Health inequality monitoring serves the core functions of quantifying situations of inequality and trends in inequality over time, informing strategies to redress inequities, and enhancing accountability for the advancement of health equity (including assessing the effectiveness of policies, programmes and practices). In some situations, health inequality monitoring may be done in response to new or renewed interest in a particular health topic or health equity-related issue. Practically, this may mean there is political and financial support for health inequality monitoring activities and the responses they prompt. Health inequality monitoring may also be done to bring attention to issues that are not (but should be) prioritized – that is, to advocate for greater visibility of a particular equity issue.
A key reason to conduct health inequality monitoring is to evaluate whether and how a health policy, programme or intervention is equity-oriented. This helps to determine which groups of people the policy, programme or intervention is reaching, and which groups are being left out.
Equity-oriented and evidence-informed action by the health sector is needed to ensure high-quality and effective services are available, accessible and acceptable in a timely manner to everyone, everywhere. Health and other sectors have a role to play in acting on wider structural determinants of health, including tackling the unfair distribution of power, wealth and other social resources.
About this resource
This book is a comprehensive and contemporary resource for health inequality monitoring, consolidating foundational and emerging knowledge in the field. It aims to support the expansion and strengthening of health inequality monitoring practices across different applications around the world, in service of the broader goal of advancing health equity.
The book is organized into four parts. Part 1 establishes the importance of health inequality monitoring and describes the components of the approach to monitoring detailed in the book:
Chapter 1 introduces and differentiates between the concepts of health inequality and health inequity and showcases the importance of health inequality monitoring and its functions within the broader goal of advancing health equity.
Chapter 2 describes the attributes of the approach to within-country inequality monitoring that is the primary focus of the book, explaining how they are distinct from complementary approaches to monitoring.
Chapter 3 describes considerations and resources to guide the selection of health topics, health indicators and dimensions of inequality for health inequality monitoring.
Chapter 4 describes the purpose and contributions of health inequality monitoring across global, regional, national and subnational levels, highlighting the range of stakeholders involved in monitoring.
Chapter 5 discusses challenges and opportunities for health inequality monitoring in selected contexts, including lower- and higher-resourced settings, rural and remote settings, refugee and migrant populations, and emergency contexts.
Part 2 offers insights into how health inequality monitoring can generate impact through integration with health system planning and policy processes, engagement with different audiences, and action beyond the health sector:
Chapter 6 demonstrates how health information systems can be oriented to promote and enable routine inequality monitoring in the health sector.
Chapter 7 aims to facilitate a deeper understanding of strategies to effectively convey key messaging about health inequalities to different audiences.
Chapter 8 introduces considerations, contexts and approaches for equity-oriented policy-making, including descriptions of primary health care, universal health coverage, and the priority public health conditions analysis framework.
Chapter 9 aims to recognize the importance of social determinants of health in understanding and addressing health inequalities, to initiate discussion about actions on social determinants of health, and to propose strategies for building and sustaining multisectoral partnerships.
Chapter 10 explores how selected themes – human rights, discrimination, colonialism and corruption – intersect with health inequalities, with examples indicating the role monitoring could play in driving and tracking their redressal.
Part 3 addresses data for health inequality monitoring, describing the characteristics of established and emerging data sources:
Chapter 11 provides foundational information about disaggregated data for health inequality monitoring, including data source quality and data security considerations. It also gives an overview of common data sources used for health inequality monitoring.
Chapter 12 describes the characteristics of household health surveys, civil registration and vital statistics systems and censuses, and discusses how each can be used for health inequality monitoring.
Chapter 13 covers the general characteristics of various institution-based data sources within the health sector (individual, service and resource records) and sources outside the health sector.
Chapter 14 discusses the main characteristics of surveillance systems and health facility assessments, highlighting how they may be used for health inequality monitoring. It also acknowledges the possibility of using data from a variety of other sources.
Chapter 15 addresses considerations for how to select data sources for health inequality monitoring, introducing techniques such as data source mapping and data source linking.
Chapter 16 introduces the key characteristics of a selection of emerging data sources, including geospatial data and technologies, mobile and web-based surveys, health tracking applications and digital public health surveillance.
Part 4 details technical aspects of monitoring related to analysis, interpretation and reporting of health inequality data, focusing on disaggregated data and summary measures of health inequality:
Chapter 17 presents technical considerations related to the preparation of disaggregated health data for analysis, with a focus on health indicator data and dimensions of inequality data, and multiple disaggregation and analysis of disaggregated data across distinct measurement levels (individual, household and small area).
Chapter 18 aims to facilitate a rigorous understanding of the conclusions derived from inspecting and comparing disaggregated health data, presenting strategies and fundamental considerations for interpreting disaggregated data.
Chapter 19 builds a theoretical understanding of the general applications and strengths and limitations of summary measures of health inequality as an extension of disaggregated data analysis.
Chapter 20 provides in-depth descriptions of pairwise summary measures of health inequality (difference and ratio) calculations, with illustrative examples of their applications.
Chapter 21 describes several complex summary measures and provides detailed information about the calculation and interpretation of selected measures.
Chapter 22 covers some of the assumptions and considerations inherent in understanding results derived from summary measures of inequality, especially when results are compared across populations and datasets.
Chapter 23 aims to enable technically rigorous, complete and visually impactful reporting of health inequality data and measurements, focusing on the technical considerations for reporting the results of inequality analysis.
Chapter 24 describes approaches and considerations for using evidence about health inequalities to inform equity-oriented decision-making.
Chapter 25 explores examples of health inequality monitoring research questions and demonstrates the application of common analytical approaches to answering them.
The epilogue provides concluding reflections on the salient messages from the book, the current reality of health inequality monitoring and future directions.
This book was developed for a diverse readership, including technical experts (e.g. statistical, planning, and monitoring and evaluation officers), public health professionals, researchers, analysts and students. Parts 1 and 2 are aimed at general audiences, but readers of Parts 3 and 4 will benefit from having a basic statistical knowledge and familiarity with monitoring-related processes and tools.
Contents are organized into 25 concise chapters, designed to be navigated by readers according to their interests and needs. The chapters do not need to be read sequentially. Concepts are illustrated through hypothetical scenarios and real-world examples. The book includes a variety of examples, recommended resources, supplementary materials, and a glossary of terms to deepen readers’ engagement with the content. The book is aligned with a broader package of tools and resources developed by the World Health Organization (WHO) to support health inequality monitoring (Box I.1).
BOX I.1: WHO resources for health inequality monitoring
As part of its commitment to advancing health equity, WHO has developed several resources to promote and strengthen health inequality monitoring activities (9). The following resources are freely available online from the Health Inequality Monitor (10).
A series of step-by-step manuals and accompanying workbooks provide practical guidance on the application of a five-step cycle of inequality monitoring in the context of national monitoring, and topics such as immunization and sexual, reproductive, maternal, newborn, child and adolescent health.
WHO State of Inequality and Explorations of Inequality reports showcase examples of high-quality, detailed technical reports on health inequality, in many cases serving as an inaugural global assessment of inequalities in the topic area.
Health Inequality Monitoring eLearning courses are free, self-directed online courses to build capacity for monitoring across diverse topics, stakeholders and settings (11). The courses cover the foundations of health inequality monitoring, applications to specific health topics, and skills-building courses.
The WHO Health Equity Assessment Toolkit (HEAT) is a free software application for analysing, interpreting and reporting inequality data (12). The software has an interactive interface that supports exploration of disaggregated data, calculation of summary measures of inequality, benchmarking between settings, and creation of graphs, maps and tables. There are two editions of the software: HEAT, built-in database edition (which has the Health Inequality Data Repository preinstalled), and HEAT Plus, upload database edition (which allows users to upload their own data).
The Health Inequality Data Repository aims to support expanded health inequality monitoring by facilitating access to disaggregated datasets across multiple health topics and settings (13). Accordingly, it is the largest publicly available collection of disaggregated data on health and its determinants. As of 2024, it contains more than 2400 indicators and 24 inequality dimensions across all world regions. Datasets can be explored interactively online using the WHO HEAT application, or they can be downloaded for external use.
Statistical codes for Excel, R, SAS, SPSS and Stata support the production of disaggregated estimates from household survey data, and the calculation of summary measures of health inequality (14).
Content development
The WHO Health Inequality Monitoring team led the conceptualization and development of the book. An Expert Review Group was established at the inception of the development, consisting of health inequality experts holding positions external to WHO. This included individuals from universities, ministries of health, government health agencies, global health partner organizations, and foundations. These experts made the following contributions: advising on the purpose, objective, components and content of the book; reviewing, revising and providing inputs to chapter drafts; and supporting the release of the book. All members of the experts group completed and submitted a declaration of interest disclosing potential conflicts of interest that might affect, or might reasonably be perceived to affect, their objectivity and independence in relation to the subject matter of this publication. WHO reviewed each of the declarations and concluded that none could give rise to a potential or reasonably perceived conflict of interest related to the subjects covered in this publication. All the experts participated in their individual capacities and not as representatives of their countries, governments or organizations.
A preliminary outline of contents was developed and refined, with input from the Expert Review Group and experts across WHO departments and regions. The Health Inequality Monitoring team drafted the chapter contents, with solicited input from experts, as required. Chapters were reviewed on a rolling basis by ERG members and relevant WHO experts, as well as other experts external to WHO, where applicable. All chapters went through at least two rounds of review. The final round of review was open to all ERG members, as well as members of the WHO Data Hub and Spoke Collaborative (which represents all areas of technical expertise across all levels of WHO).
The contents of the book build on the 2013 Handbook on health inequality monitoring in low- and middle-income countries (15). Content development was informed by WHO acquired expertise and experiences leading capacity building activities for health inequality monitoring with Member States and global health partners over the past 20 years. Academic and grey literature was reviewed systematically.
Efforts were made to ensure the examples represent a diverse range of health topics and geographical settings to demonstrate the wide applicability of health inequality monitoring3. Key sources included technical reports and publications, academic journal articles and reputable webpages maintained by government health agencies, international organizations and authoritative institutions. In some chapters, the book adapted materials developed for the WHO Health Inequality Monitoring eLearning channel (11). The data featured in examples were primarily sourced from the WHO Health Inequality Data Repository (13).
The contents of this book are accessible online through a dedicated webpage (https://www.who.int/data/inequality-monitor/tools-resources/book_2024).
A note on terminology
Throughout the book, we have endeavoured to use language and terminology that reflect inclusivity and respect for all individuals and population subgroups. In our discussions of population subgroups, we acknowledge the inherent diversity within these groups, and the intersectional nature of the characteristics that influence and shape health experiences. When referring to subgroups that experience “disadvantage”, the intention is to recognize specific historic and systemic factors linked to relative social disadvantage, such as lower economic status or education level. This and other terminologies are not meant to convey negative stereotypes, stigmatization or blame.
References
1. Global health estimates: life expectancy and healthy life expectancy. Geneva: World Health Organization (https://www.who.int/data/gho/data/themes/mortality-and-global-health-estimates/ghe-life-expectancy-and-healthy-life-expectancy, accessed 29 August 2024).
2. Global health estimates: leading causes of DALYs. Geneva: World Health Organization (https://www.who.int/data/gho/data/themes/mortality-and-global-health-estimates/global-health-estimates-leading-causes-of-dalys, accessed 22 August 2024).
3. World Health Organization, World Bank. Tracking universal health coverage: 2023 global monitoring report. Geneva: World Health Organization; 2023 (https://iris.who.int/handle/10665/374059, accessed 4 September 2024).
4. State of inequality: HIV, tuberculosis and malaria. Geneva: Geneva: World Health Organization; 2021 (https://iris.who.int/handle/10665/350198, accessed 4 September 2024).
5. World Health Organization, United Nations Children’s Fund. Ending preventable child deaths from pneumonia and diarrhoea by 2025: the integrated Global Action Plan for Pneumonia and Diarrhoea (GAPPD). Geneva: World Health Organization; 2013 (https://iris.who.int/handle/10665/79200, accessed 29 August 2024).
6. World health statistics 2023: monitoring health for the SDGs, sustainable development goals. Geneva: World Health Organization; 2023 (https://iris.who.int/handle/10665/367912, accessed 3 September 2024).
7. Singh D, Vignat J, Lorenzoni V, Eslahi M, Ginsburg O, Lauby-Secretan B, et al. Global estimates of incidence and mortality of cervical cancer in 2020: a baseline analysis of the WHO Global Cervical Cancer Elimination Initiative. Lancet Glob Health. 2023;11(2):e197–206. doi:10.1016/S2214-109X(22)00501-0.
8. Health equity. Geneva: World Health Organization (https://www.who.int/health-topics/health-equity, accessed 4 September 2024).
9. Hosseinpoor AR, Bergen N, Kirkby K, Schlotheuber A. Strengthening and expanding health inequality monitoring for the advancement of health equity: a review of WHO resources and contributions. Int J Equity Health. 2023;22(1):49. doi:10.1186/s12939-022-01811-4.
10. Health Inequality Monitor. Geneva: World Health Organization (https://www.who.int/data/inequality-monitor, accessed 4 September 2024).
11. Training. Geneva: World Health Organization (https://www.who.int/data/inequality-monitor/training, accessed 4 September 2024).
12. Health Equity Assessment Toolkit (HEAT). Geneva: World Health Organization (https://www.who.int/data/inequality-monitor/assessment_toolkit, accessed 4 September 2024).
13. Health Inequality Data Repository. Geneva: World Health Organization (https://www.who.int/data/inequality-monitor/data, accessed 15 October 2024).
14. Statistical codes for health inequality analysis. Geneva: World Health Organization (https://www.who.int/data/inequality-monitor/tools-resources/statistical_codes, accessed 4 September 2024).
15. Handbook on health inequality monitoring with a special focus on low- and middle-income countries. Geneva: World Health Organization; 2013 (https://iris.who.int/handle/10665/85345, accessed 4 September 2024).
Coinciding with the first years of the COVID-19 pandemic, the 2019–2021 period saw substantial setbacks in health, including declines in global life expectancy and healthy life expectancy.↩︎
Between 2019 and 2021, there was no reported change in terms of global progress towards universal health coverage.↩︎
A paucity of relevant data for certain contexts meant these efforts were incomplete. The authors encourage the expanded collection of disaggregated data and adoption of health inequality monitoring within new frontiers.↩︎