Glossary

absolute inequality a magnitude of difference in health between subgroups. Absolute measures of inequality, such as absolute difference, retain the same unit of measurement as the health indicator.

accessibility in the context of data quality, the ease with which users can find, retrieve, understand and use data.

accuracy in the context of data quality, the degree of closeness estimates are to the true values.

adverse health indicator a health indicator that has an inverse relationship with health such that lower values are generally regarded as better. Indicators that measure the burden of disease, non-use of essential services, lack of knowledge, and unhealthy behaviours and attitudes are usually adverse health indicators.

affected population the individuals, populations and communities (typically defined by geographical area, age or life stage) that are the focus of inequality monitoring analyses, and for whom equity-oriented actions seek to benefit.

benchmarking comparisons of inequality across similar areas or populations to get a sense of how one area or population performs in relation to others. Benchmarking promotes a broader understanding of the state of inequality.

between-country health inequality differences in health across two or more countries. Analysis of between-country health inequality may entail comparisons between single countries, or between defined groups of countries (e.g. low-income versus high-income countries).

census a periodic enumeration of a population that systematically records identities of all individuals in every place of residence, along with information about age or birth date, sex, socioeconomic status, marital status, race or ethnicity, household composition and size, and geographical area. In some cases, other items of information may be collected.

change over time in the context of health inequality monitoring, a comparison of the situation of inequality at multiple points in time, demonstrating the extent to which inequalities have increased, stayed the same or decreased.

civil registration the continuous, permanent, compulsory and universal recording of the occurrence and characteristics of vital events pertaining to the population, as provided through decree or regulation in accordance with the legal requirements in each country.

civil registration and vital statistics see Civil registration and Vital statistics.

common identifier individual or small-area information that is present in multiple data sources and can be used to link data; see also Data source linking.

community-based monitoring mechanisms that service users or local communities use to gather, analyse and use information on an ongoing basis to improve the access, quality and impact of services, and to hold service providers and decision-makers to account.

completeness in the context of data quality, all required data for the health indicator and inequality dimension are present and, if applicable, representative of the population of interest.

complex summary measure of inequality a measure that draws on disaggregated data from all population subgroups, yielding a single number that expresses the level of inequality. For example, complex measures of inequality can express inequality across all five wealth quintiles, or across all districts in a country.

composite indicator an index composed of several indicators within a health topic to represent that topic. A composite indicator may combine indicators from across several health topics to represent a broader concept, such as universal health coverage.

compounded advantage a scenario where certain demographic, socioeconomic and geographic conditions act together to enhance advantage.

compounded vulnerability a scenario where certain demographic, socioeconomic and geographic conditions act together to exacerbate vulnerability.

confidence interval a range of values used to quantify the imprecision in the estimate of a particular value. Specifically, it quantifies the imprecision that results from random variation in the estimation of the value. It does not include imprecision resulting from systematic error (bias).

confounding variable an additional variable related to the independent and dependent variables and that distorts the relationship between them.

covariates variables, including non-health data, used in a statistical model to improve the estimation of the health indicator of interest. These variables are population-specific and are available for every population included in the analysis. A common covariate is gross domestic product per capita.

credibility in the context of data quality, confidence that users place in the statistics.

data governance a framework or mechanism that builds and maintains trust in data (and the institution producing and holding the data) by managing transparently the access, use and reuse (including matching and linking), quality and security of those data to maximize the net benefits.

data sources for the purposes of health inequality monitoring, data sources contain quantitative information about health indicators or dimensions of inequality for a population of interest. In some cases, monitoring will involve the use of a single data source that contains all relevant information. In other cases, data may be drawn from several different sources.

data source linking merging information about health indicators and dimensions of inequality from different data sources using individual or small-area identifiers.

data source mapping a systematic process for cataloguing and describing all data available for health inequality monitoring in a given context. The process can be broken down into four sequential stages: list available data sources by type; for each data source, determine the availability of data for dimensions of inequality; for each data source, determine the availability of data about health indicators; and combine the lists about health indicators and dimensions of inequality.

decomposition analysis breaking down the separate contributions of measurable characteristics (e.g. education, place of residence, socioeconomic status) to inequality in a health indicator.

denominator the lower portion of a fraction used to calculate a rate or ratio. In a rate, the denominator is often defined as the population at risk.

deprivation index a composite measure that combines information about multiple indicators within one or more dimensions of inequality, often at the small-area level.

determinants of health factors that combine to affect the health of individuals and communities. Determinants of health include the social and economic environment, the physical environment, and the person’s individual characteristics and behaviours.

digital health systematic application of information and communications technologies, computer science and data to support informed decision-making by individuals, the health workforce and health systems to strengthen resilience to disease and improve health and wellness.

dimensions of inequality criteria upon which population subgroups are categorized for inequality monitoring. Examples of dimensions of inequality include age, economic status, education level, place of residence, sex and subnational region.

disaggregated health data data on health or determinants of health, by population subgroups defined by one or more dimensions of inequality. Disaggregated data can show underlying inequality patterns that are not evident from overall averages across a population.

double disaggregation the practice of filtering data according to two dimensions of inequality simultaneously. Double and multiple disaggregation permits a quantitative exploration of intersectionality.

ecological analysis analysis based on aggregated or grouped data, such as analysis of the relationship between a health indicator and a health determinant or exposure at a population level.

ecological fallacy an erroneous inference that may occur because an association observed between variables on an aggregate level does not necessarily represent or reflect the association that exists at an individual level. A causal relationship that exists on a group level or among groups may not exist among the individuals in the group.

equity stratifier see Dimensions of inequality.

estimate indicator value calculated based on a single data source, such as a household survey or institution-based data source, taking into account relevant assumptions and limitations of the data source.

evaluation a process that attempts to determine as systematically and objectively as possible the relevance, effectiveness and impact of activities in the light of their objectives.

evidence-informed decision-making a systematic and transparent approach that applies structured and replicable methods to identify, appraise and make use of evidence across decision-making processes, including for implementation.

favourable health indicator a health indicator that has a positive relationship with health, such that higher values are generally regarded as better. Indicators that measure the use of essential services, healthy behaviours and attitudes, family and community connectedness, and positive health outcomes are usually favourable health indicators.

geographic information system (GIS) a system that creates, manages, analyses and maps geospatial data.

geospatial data data about objects, events or other features that have a location on the surface of the earth.

health equity absence of unfair, avoidable or remediable differences in health among population subgroups defined socially, economically, demographically or geographically.

health facility census periodic enumeration of all public and private health-care facilities within a country about the facilities and the services they provide.

health facility survey periodic enumeration of a representative sample of public and private health-care facilities within a country about the facilities and the services they provide.

health indicator a measurable quantity that can be used to describe a population’s health or its determinants.

health inequality measured difference in health between population subgroups. Health inequalities can be measured and monitored. For the past three decades, the term has been used globally to refer to health differences associated with social advantage and disadvantage.

health inequity unfair, avoidable or remediable differences in health among groups of people. In some cases, the absence of a difference between groups (i.e. a situation of equality) might be considered inequitable. Health inequity is rooted in the unfair distribution of, and unfair access to, power, wealth and other social resources, and is linked to forms of disadvantage that are socially produced, such as poverty, discrimination and lack of access to services or goods.

health information system a system that integrates data collection, processing, reporting and use of the information necessary for improving health service effectiveness and efficiency through better management at all levels of health services.

household health survey a data source that collects information from a representative sample of a study population about a variety of health indicators and a range of dimensions of inequality. Survey data are used to generate disaggregated estimates based on a specified sampling design within a population.

impact indicator an indicator that measures long-term outcomes that programmes are designed to affect, including changes in mortality and morbidity.

indicator see Health indicator.

input indicator an indicator that measures human and financial resources, physical facilities, equipment and operational policies that enable programme activities to be implemented. This includes health financing, health workforce, health infrastructure, and health information and governance.

institution-based data source a source that contains information collected in the course of administrative and operational activities. Examples include records kept by health facilities or institutions outside the health sector.

interaction when the relationship between two variables depends on the value of another variable (also referred to as effect modification).

intersectionality a concept describing how interconnected dimensions of inequality (especially gender, income/wealth and race/ethnicity) interact to create different experiences of privilege, vulnerability or disadvantage.

intersectoral action see Multisectoral action.

intervention an action or programme that aims to bring about identifiable outcomes or changes.

Leave No One Behind a guiding principle of the Sustainable Development Goals encompassing a commitment to eradicating poverty in all forms, ending discrimination and exclusion, and reducing inequalities and vulnerabilities that undermine the potential of individuals and humanity on whole.

linking see Data source linking.

median the middle point of a set of ordered numbers, such that half of the values are higher and half of the values lower than the median.

metadata data that define or describe other data. They are the information needed to explain and understand the data or values being presented. In the context of inequality monitoring, metadata often include detailed information related to data collection, spatial and temporal coverage of data sources, indicators, dimensions of inequality, methods of data disaggregation and summary measure calculation.

methodological soundness in the context of data quality, the application of the available international standards, guidelines and good practices in the production of data.

modelled estimates indicator values that draw from different sources of data, information and expertise and use established, standardized methods to produce estimates that are comparable across settings.

monitoring systematic and routine collection of information to assess performance and progress towards specific targets and over an established period of time.

multiple disaggregation the practice of filtering data according to more than two dimensions of inequality simultaneously. Double and multiple disaggregation permits a quantitative exploration of intersectionality.

multiple regression a statistical technique used to analyse the relationship between a single dependent variable and several independent variables. In the context of health inequality analyses, multiple regression can provide information about the dimensions of inequality that are most associated with a health indicator.

multisectoral action the involvement of several sectors in developing and implementing public policies intended to improve health, equity, well-being and other policy outcomes.

non-ordered dimension of inequality inequality dimensions that are not based on criteria that can be logically ranked. For example, ethnicity, region and religion dimensions of inequality typically contain non-ordered subgroups.

ordered dimension of inequality inequality dimensions that have an inherent positioning and can be logically ranked. For example, education has an inherent ordering of subgroups, because people with less education unequivocally have less of something compared with people with more education.

outcome indicator an indicator that measures whether a programme is achieving the expected effects or changes in the short, intermediate and long term. Some programmes refer to their longest-term or most distal outcome indicators as impact indicators. This usually includes coverage of interventions, risk factors and behaviours.

output indicator an indicator that measures the results of the processes in terms of service access, availability, quality, safety and health security.

pairwise summary measure of inequality the comparison of health between two subgroups using difference or ratio. Pairwise measures of inequality are unweighted.

population share the percentage of people in the affected population that is represented in a given population subgroup.

population shift a phenomenon that occurs when the distribution of the population across subgroups (i.e. the population share) changes over time.

population size the absolute number of people in the affected population that is represented in a given population subgroup.

population subgroup a subset of a larger population that shares a certain characteristic. For the purposes of health inequality monitoring, population subgroups are defined by a dimension of inequality.

population-based data source a data source that contains information on every individual in an affected population or a representative sample of an affected population.

primary health care a whole-of-society approach to health that aims to maximize the level and equitable distribution of health and well-being by focusing on people’s needs and preferences as early as possible along the continuum, from health promotion and disease prevention to treatment, rehabilitation and palliative care. Primary health care encompasses three mutually dependent components: integrated primary care services and essential public health functions; multisectoral policy and action; and individual empowerment and community engagement.

process indicator an indicator that measures a programme’s activities and outputs (direct products or deliverables of the activities). Together, measures of activities and outputs indicate whether the programme is being implemented as planned (e.g. health workforce training, constructing a health facility, registering births and deaths).

progressive universalism an approach to reaching universal health coverage that ensures disadvantaged populations realize equal or greater gains until the goal of universalism is eventually approached.

proxy indicator an indicator that stands in for another indicator or topic that is difficult to measure or for which data are limited.

public health significance the relevance or meaning from a public health perspective.

reference point a defined value, such as a subgroup estimate, overall measure or target, against which subgroups are compared.

regression a statistical technique that relates a dependent variable to one or more independent (explanatory) variables.

relative inequality the proportional difference in health among population subgroups. Relative measures of inequality, such as ratio, are unitless.

relevance in the context of data quality, the degree to which data meet users’ needs.

reliability in the context of data quality, the consistency of the data when collected repeatedly using the same procedures and under the same circumstances.

resolution issues misleading situations that arise when comparing summary measures of inequality based on disaggregated data with variable numbers of subgroups.

sample size the number of people upon which a disaggregated (subgroup) estimate is based – that is, the denominator used to calculate a disaggregated estimate.

simple summary measure of inequality see Pairwise summary measure of inequality.

small-area identifier information attributed to small areas, such as postal codes or census tracts, that is present in multiple data sources and can be used to link data; see also Data source linking.

social determinants of health the conditions in which people are born, grow, work, live and age, and people’s access to power, money and resources.

statistical significance a mathematical measure of the probability that a result is likely due to chance or another factor (i.e. the null hypothesis).

subgroup see Population subgroup.

summary measure of inequality a measure of the level of inequality between two or more subgroups, expressed as a single number. Summary measures of inequality can be characterized as absolute or relative, and weighted or unweighted, and can draw from two subgroups (pairwise measures) or more than two subgroups (complex measures).

surveillance system a system for detecting, reporting and responding to specific notifiable conditions – usually epidemic-prone communicable diseases. Surveillance systems draw data from a range of other data sources.

survey an investigation about the characteristics of a given population by means of collecting data from a sample of that population and estimating their characteristics through the systematic use of statistical methodology.

timeliness in the context of data quality, the availability and reliability of data at the time they are needed to construct indicators.

tracer indicator an indicator chosen as an example to represent a broader health topic.

uncertainty measure a measure that indicates the accuracy with which an estimate from a sample represents the population. Common uncertainty measures include 95% confidence intervals and standard error.

universal health coverage a health system goal in which all people have access to the full range of good-quality health services they need, when and where they need them, without financial hardship. It covers the full continuum of essential health services, from health promotion to prevention, treatment, rehabilitation and palliative care.

unweighted summary measure of inequality a pairwise or complex measure of inequality that treats each subgroup as equally sized.

vital events events concerning life and death of individuals and their family and civil status, including live births, adoptions, legitimations and recognitions; deaths and fetal deaths; and marriages, divorces, separations and annulments of marriage.

vital statistics a systematic record of vital events to generate data and statistics. The components of a vital statistics system are legal registration; statistical reporting of vital events; and collection, compilation and dissemination of statistics pertaining to those events.

weighted summary measure of inequality a complex measure of inequality that takes into account the population size of each subgroup.

within-country health inequality differences in health across two or more subgroups of a national or subnational population.

Notes

Terms are defined according to their intended application to the health inequality monitoring concepts discussed in this book; terms may have other meanings in other contexts. Many of the terms are used across World Health Organization health inequality monitoring tools and resources, available here:

Health inequality monitor. Geneva: World Health Organization (https://www.who.int/data/inequality-monitor/tools-resources, accessed 9 July 2024).

Definitions were also adapted from the following sources:

Commonly used public health statistics and their confidence intervals: technical briefing 3. York: Association of Public Health Observatories; 2010 (https://fingertips.phe.org.uk/documents/APHO%20Tech%20Briefing%203%20Common%20PH%20Stats%20and%20CIs.pdf, accessed 9 July 2024).

Epidemiology glossary. Atlanta, GA: Centers for Disease Control and Prevention (https://www.cdc.gov/reproductive-health/glossary/, accessed 16 July 2024).

Community-based monitoring: an overview. Geneva: Global Fund to Fight AIDS, Tuberculosis and Malaria; 2020 (https://www.theglobalfund.org/media/9622/core_css_overview_en.pdf, accessed 11 June 2024).

Greenwell F, Salentine S. Health information system strengthening: standards and best practices for data sources. Chapel Hill, NC: United States Agency for International Development; 2018 (https://www.measureevaluation.org/resources/publications/tr-17-225/at_download/document, accessed 16 July 2024).

Gwatkin DR, Ergo A. Universal health coverage: friend or foe of health equity? Lancet. 2011;377(9784):2160–2161. doi:10.1016/S0140-6736(10)62058-2.

Health Metrics Network. Framework and standards for country health information systems, second edition. Geneva: World Health Organization; 2008 (https://iris.who.int/handle/10665/43872, accessed 15 May 2024).

Porta M. A dictionary of epidemiology. Oxford: Oxford University Press; 2016.

Rajan D, Rouleau K, Winkelmann J, Kringos D, Jakab M, Khalid F, editors. Implementing the primary health care approach: a primer. Geneva: World Health Organization; 2024 (https://iris.who.int/handle/10665/376777, accessed 16 July 2024).

SDMX content-oriented guidelines: metadata common vocabulary. SDMX; 2006 (https://sdmx.org/wp-content/uploads/Content_04_Draft_Guidelines_Metadata_Common_Vocabulary-MARCH-2006-1.pdf, accessed 11 July 2024).

Stevens GA, Alkema L, Black RE, Boerma JT, Collins GS, Ezzati M, et al. Guidelines for accurate and transparent health estimates reporting: the GATHER statement. Lancet. 2016;388(10062):E19–E23. doi: 10.1016/S0140-6736(16)30388-9

Stock K, Guesgen H. Geospatial reasoning with open data. In: Layton R, Watters P, editors. Automating open source intelligence. Waltham, MA: Elsevier; 2016.

Tenny S, Abdelgawad I. Statistical significance. St Petersburg, FL: StatPearls Publishing; 2023 (https://www.ncbi.nlm.nih.gov/books/NBK459346/, accessed 11 July 2024).

Handbook on civil registration and vital statistics systems: management, operation and maintenance, revision 1. New York: United Nations Department of Economic and Social Affairs; 2021 (https://unstats.un.org/unsd/demographic-social/Standards-and-Methods/files/Handbooks/crvs/crvs-mgt-E.pdf, accessed 11 July 2024).

Principles and recommendations for a vital statistics system, revision 3. New York: United Nations Department of Economic and Social Affairs; 2014 (https://unstats.un.org/unsd/demographic-social/Standards-and-Methods/files/Principles_and_Recommendations/CRVS/M19Rev3-E.pdf, accessed 15 May 2024).

United Nations Statistical Division. Data quality framework. Presented at the Regional Workshop on International Merchandise Trade Statistics, September 2017, Suzhou, China (https://unstats.un.org/unsd/trade/events/2017/suzhou/presentations/Agenda%20item%2014%20-%20UNSD%20(revised).pdf, accessed 15 May 2024).

Terminology on statistical metadata. Conference of European Statisticians Statistical Standards and Studies, no. 53. Geneva: United Nations Statistical Commission and Economic Commission for Europe; 2000 (https://unece.org/DAM/stats/publications/53metadaterminology.pdf, accessed 11 July 2024).

Social determinants of health. Geneva: World Health Organization (https://www.who.int/health-topics/social-determinants-of-health, accessed 20 June 2024).

Classification of digital interventions, services and applications in health: a shared language to describe the uses of digital technology for health, second edition. Geneva: World Health Organization; 2023 (https://iris.who.int/handle/10665/373581, accessed 11 July 2024).

Universal health coverage (UHC). Geneva: World Health Organization; 2023 (https://www.who.int/news-room/fact-sheets/detail/universal-health-coverage-(uhc), accessed 23 May 2024).

Working together for equity and healthier populations: sustainable multisectoral collaboration based on Health in All Policies approaches. Geneva: World Health Organization; 2023 (https://iris.who.int/handle/10665/372714, accessed 19 June 2024).

Evidence, policy, impact: WHO guide for evidence-informed decision-making. Geneva: World Health Organization; 2021 (https://iris.who.int/handle/10665/350994, accessed 20 June 2024).

Incorporating intersectional gender analysis into research on infectious diseases of poverty: a toolkit for health researchers. Geneva: World Health Organization; 2020 (https://iris.who.int/handle/10665/334355, accessed 20 June 2024).

Data quality review: a toolkit for facility data quality assessment. Module 1: framework and metrics. Geneva: World Health Organization; 2017 (https://cdn.who.int/media/docs/default-source/world-health-data-platform/rhis-modules/dqa-module-1-framework-and-metrics.pdf?sfvrsn=bdbfa280_2, accessed 15 May 2024).

Determinants of health. Geneva: World Health Organization; 2017 (https://www.who.int/news-room/questions-and-answers/item/determinants-of-health, accessed 15 May 2024).

Guidelines for the development of health management information systems. Manila: World Health Organization Regional Office for the Western Pacific; 1993 (https://iris.who.int/handle/10665/207002, accessed 7 May 2024).