Independent Research— Health Inequality

There is a strong connection between socioeconomic status and health. This correlation has been well documented over the past few decades, and health inequalities have been shown to appear early and peak around the time of early old age (late fifties, early sixties). Among the elderly this correlation diminishes, partly because of social policies like Medicare and Social Security and partly because of self-selection (only the healthiest live to advanced ages).

I set out this summer to study health inequalities during recessions, and as a first step I tested the level of health inequality. My research has been focusing on this elderly population, looking at Medicare recipients (age 65+) who live in the community (not in a facility). Even though other studies suggested that by this age cohort the health inequality relationship might be weaker, I found that it was still very strong even when controlling for demographics (race, sex, marital status, age) and location. Socioeconomic status can be measured in many ways, but I used income level and education as measures of SES.

These graphs show the relationship between income and the general health of the respondent, the respondent’s health compared to one year ago, and the number of difficulties the respondent has with activities of daily living (ADLs). The graphs show the mean income for the group of respondents for each health measure. There is a clear positive relationship between higher income and better health.

Additionally, in fixed effect regressions on each of these health outcome variables, income and income squared were found to be highly statistically significant although in opposite directions. As expected, higher income decreased a respondent’s likelihood of reporting fair or poor health (compared to excellent, very good, or good) for the general health variable, but the income squared term was positive (increasing the likelihood of worse health). This suggests that while income does correlate with better health, the magnitude of its effect decreases at higher values.  Education was also highly significant, with more education correlating with better health.

One of the biggest challenges in health stratification today is figuring out why this relationship exists. The descriptive statistics and regressions say that, yes, there is health inequality in this population, but it tells us nothing about causality. Does being poor make you sick, or does being sick make you poor? This is the mystery that researchers in the field today are trying to unravel. What can I say about the results? It seems that the social welfare policies for the elderly are not eradicating health inequalities. One possible useful explanation is to think of health as a stock built up over a lifetime, with choices and environments building up or depleting that stock. Changes making medical care or retirement available so late in life may be too late to affect overall health stock.


  1. Hey Ashley, this is an interesting topic to examine. Like you said, it’s very difficult to determine if socioeconomic status is causing poor health or vice versa. It makes sense that being poor and not having adequate assets for proper nutrition and preventative care would be detrimental to one’s health. Still, an individual who is sick for a lengthy period of time has reduced ability to earn income. Without having any real knowledge of the subject, the impact of socioeconomic status on health seems greater than the other way around, but it is of course a very difficult question to answer.

  2. Hi Ashley — This sounds like an interesting and complex issue to investigate. I was wondering if you differentiate in any way between income and wealth. This distinction seems especially pertinent in older populations who might currently have similar fixed incomes, but could have had huge differences in income prior to retirement. Does the research in the field ever address this issue?