• Societal Outcome (Foundational Standard):  Population health needs are anticipated, identified, addressed, and evaluated.

 Assessment and/or Surveillance Requirements Related to this Indicator

• The board of health shall assess current health status, health behaviours, preventive health practices, health care utilization relevant to public health, and demographic indicators in accordance with the Population Health Assessment and Surveillance Protocol, 2008 (or as current) (Foundational Standard)
• The board of health shall conduct surveillance, including the ongoing collection, collation, analysis, and periodic reporting of population health indicators, as required by the Health Protection and Promotion Act and in accordance with the Population Health Assessment and Surveillance Protocol, 2008 (or as current) (Foundational Standard).

 Protocol Requirements Related to this Indicator

• The board of health shall collect or access the following types of population health data and information: Socio-demographics including population counts… (Population Health Assessment and Surveillance Protocol, Data Access, collection and management, 1b)  

http://www.ontario.ca/publichealthstandards

Corresponding Health Indicator(s) from Statistics Canada and CIHI

The internet publication Health Indicators, produced jointly by Statistics Canada and the Canadian Institute for Health Information, provides over 80 indicators measuring the health of the Canadian population and the effectiveness of the health care system. Designed to provide comparable information at the health region and provincial/territorial levels, these data are produced from a wide range of the most recently available sources.  A pdf copy of the Health Indicators e-publication report can be found on CIHI’s website (http://www.cihi.ca) at http://www.cihiconferences.ca/indicators/2012/ind2012_e.html

Corresponding Mandatory Objectives

• None

Corresponding National Indicators

Suggested citation (see Data Citation Notes):
[year] Census (special tabulations), Statistics Canada, National Household Survey
[year] National Household Survey, Statistics Canada

Analysis Check List

None

TIBM: Total income of all households below the median income
TIA: Totall income of all households

Median Share of Income = TIBM / TIA x 100 (expressed as a %)

Example A: Median income of Health Region (HR) A is $20,000. The total income of the half of households in HR A whose incomes fall below the median is $1,000,000. The income of the households in this HR whose incomes are above the median is $4,000,000. Thus, the proportion of income held by the bottom half of households in HR A, that is, the median share of income, is (1,000,000/5,000,000) = 20%.

Example B: The median household income within HR B is also $20,000. The total income of the half of households in HR B whose incomes fall below the median is $1,000,000. The income of the households in this HR whose incomes are above the median is $6,000,000. Thus, the proportion of income held by the bottom half of households in this HR, that is, the median share of income, is (1,000,000/7,000,000) = 14%.

These examples demonstrate that two HRs with identical median household incomes may differ in their distribution of household income, i.e., HR B has greater income inequality.

Basic Categories

• Geographic areas: public health unit, LHIN.

Indicator Comments

• The “income inequality hypothesis” states that disparities in income among members of a community affect their health, and specifically, that economically egalitarian communities or societies have better health outcomes than more unequal communities.
• Income inequality should be measured by a combination of indicators.  There is no one single measure of low income or income inequality, but there are measures that can be used in conjunction with others to provide some context to the income sphere (eg. Ginni coefficient, the ratio of 90% over 10% after tax income, the Survey of Labour and Income Dynamics (SLID), or share of income by quintile (bottom 4%, top 40%).  Statistics Canada recommends using the Gini coefficient. 
• The Gini coefficient is a number between zero and one that measures the relative degree of inequality in the distribution of income.  The coefficient would register zero (minimum inequality) for a population in which each person received exactly the same adjusted family income and it would register a coefficient of one (maximum inequality) if one person received all the adjusted family income and the rest received none. Even though a single Gini coefficient value has no simple interpretation, comparisons of the level over time or between populations are very straightforward: the higher the coefficient, the higher the inequality of the distribution, and vice versa.
• The Gini coefficient is not readily available below the level of the province of Ontario. 
• The median share of income is one of the measures of income inequality that is readily available at the health unit level from Statistics Canada.
• In low-income comparisons across time or across countries/regions, it is often more desirable to view low income in relative terms, as the low-income line is defined as some proportion of median or average income in respective time periods or regions.  

Cross-References to Other Indicators

1. Sanga D. Income inequality within provinces. Perspectives on labour and income 2000;1(02):33-38.
2. Weinberg DH. A Brief Look at Postwar U.S. Income Inequality. Washington: Bureau of the Census, Economics and Statistics Administration, U.S. Department of Commerce; 1996, June. Report No. P60-191. Available from: URL: http://www.census.gov/prod/1/pop/p60-191.pdf
3. Ross NA,Wolfson MC, Dunn JR, Berthelot JM, Kaplan GA, Lynch JW. Relation between income inequality and mortality in Canada and the United States: cross sectional assessment using census data and vital statistics. BMJ 2000;320:898-902.
4. Wilkinson RG. Unhealthy societies: the affliction of inequality. London: Routledge, 1996.
5. Lynch JW, Smith GD, Kaplan GA, House JS. Income inequality and mortality: importance to health of individual income, psychosocial environment, or material conditions. BMJ 2000;320:1200-1204.
6. Mackenbach JP. Income inequality and population health. BMJ 2002;324:1-2.
7. Statistics Canada. Data and definitions of income and low-income lines.  2009. Available at:   http://www.statcan.gc.ca/pub/75f0002m/2008006/a5-eng.htm
8. Xi G, McDowell I, Nair R, Spasoff, R. Income inequality and health in Ontario: A multilevel analysis. Canadian Journal of Public Health 2005;9(3):206-211.
9. Wong, CH. The Gini Coefficient of income disparity of Ontario by Census Divisions in 1996 and 2001. Public Health and Epidemiology Report Ontario (PHERO). 2003 Sep 30:130-5.  Available from:  http://www.health.gov.on.ca/english/providers/pub/pub_menus/pub_phero/pub_phero_2003.html