Health Disparities Interest Group December 2008 Seminar
The Health Disparities Interest Group (HDIG) seminar on December 12, 2008 featured dynamic presentations on methods for measuring and calculating health disparities. Dr. Sam Harper and his colleague, Dr. John Lynch, have worked under contract with staff in the National Cancer Institute, Division of Cancer Control and Population Sciences (DCCPS)'s Applied Research Program (ARP) and Surveillance Research Program (SRP) since 2003. This team has produced two monographs and several articles examining measures of health disparities and how their results vary. Steve Scoppa and his Information Management Services (IMS) colleague, Dave Campbell, have worked with this team since 2007 to develop the forthcoming disparities calculator software, HD*Calc. HD*Calc makes a range of health disparities measures accessible to users. DCCPS support for this collaborative project includes providing funding for one of the monographs.
Methods for Measuring Health Disparities
Dr. Sam Harper, PhD, of McGill University discussed indices used to report health disparities and highlighted important considerations for selecting and interpreting them. Key points made by Dr. Harper include the following.
- Two measures may lead to opposite conclusions concerning whether health inequality is increasing or decreasing over time. To fully understand current disparities in a particular health area and progress made in eliminating them, it is important to examine multiple, complementary measures (e.g. indices of both absolute and relative inequalities).
- Most studies of health inequalities have focused exclusively on ratios, which can be misleading. Knowing the underlying, absolute rates provides more accurate and complete information if only a single index is used.
- Population size and shifts in demographics must be examined in order to fully understand disease burden. Using population weighting can reveal inequality that would otherwise be masked.
- A utilitarian approach to health disparities measurement values progress made over time in a particular health area (e.g. smoking rates) equally for all subpopulations in the distribution. A prioritarian approach, on the other hand, gives greater priority to subpopulations who are worse off at the outset. These approaches are implicit in all health disparities indices, so it is important that researchers use an index taking the approach they wish to emphasize, and inform readers of this.
- Measures of health inequality are not value neutral. Decisions regarding measurement scale and weighting (how much and to whom) have an important impact on judgments of both the magnitude of health inequality and whether health inequalities are worsening or improving.
Related monographs by Dr. Harper and Dr. John Lynch are available:
- Harper S, Lynch J. Methods for Measuring Cancer Disparities: Using Data Relevant to Healthy People 2010 Cancer-Related Objectives. NCI Cancer Surveillance Monograph Series, Number 6. Bethesda, MD: National Cancer Institute, 2005. NIH Publication No. 05-5777. [View and Download]
- Harper S, Lynch J. Selected Comparisons of Measures of Health Disparities: A Review Using Databases Relevant to Healthy People 2010 Cancer-Related Objectives. NCI Cancer Surveillance Monograph Series, Number 7. National Cancer Institute. NIH Pub. No. 07-6281, Bethesda, MD, 2007. [View and Download]
- Harper S, Lynch J, Meersman SC, Breen N, Davis WW, Reichman ME. An overview of methods for monitoring social disparities in cancer with an example using trends in lung cancer incidence by area-socioeconomic position and race-ethnicity, 1992-2004. American Journal of Epidemiology 2008 Apr 15;167(8):889-99. [View Full Text]
Additional publications on this topic are forthcoming.
Disparities Calculator Demonstration: HD*Calc
Mr. Steve Scoppa of Information Management Services (IMS) demonstrated the beta version of a new disparities calculator program, HD*Calc, and how it can be used to analyze data. HD*Calc evolved from SEER*Stat to examine data from the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) Program. HD*Calc can now be used to analyze any data imported by users. Thus, one highly useful feature of the program is its Dictionary file, which saves all criteria and values that have been specified by the user to accompany data from any source.
HD*Calc is planned for public release in early 2009.
Last Modified: 03 Sep 2013