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July 2015

Oakland County – By The Numbers

Oakland County – By The Numbers

By Sabiha Zainulbhai

Detroit By The Numbers: A WDET and D3 Partnership

We’ve seen news articles and public officials publicizing Oakland County as one of “the wealthiest counties in the country,” But where does this statistic come from? Does Oakland County make it in the top ten? Does it even come close?

As part of WDET and Data Driven Detroit’s (D3) new segment—Detroit by the Numbers—we demystify widely-held myths about the region to tell the stories behind the numbers. You can check out our full story (including interviews and maps) from the past two segments, Oakland County and poverty, as well as our upcoming segment on Detroit parks at

Demystified: Oakland County — By The Numbers

To understand where the statement regarding Oakland County first came from, we did some digging. Our analysts found that Oakland County ranks itself “with other like counties,” i.e. among counties that also exceed a million people.2 We found that out of the 3,144 counties in the US, Oakland County is one of only 41 counties whose population exceeds 1 million people. As Erica Raleigh, executive director of D3 points out, understanding these qualifiers is critical to contextualizing any kind of data, and could be the key to separating fact from fiction.

Next, we worked to unpack what “wealth” means in the US, looking first at several measures of income. Income per capita, median household income, and personal income per capita: all of which measure in different ways how much a person, a family or a geographic area earns from wages and other sources over a certain period of time.

Income: The Measure You Choose Matters3

  • US Census Bureau’s Median Household Income is perhaps the most widely used and accepted measure of income. It takes into account all households in an area, and includes anyone in a household that is 15 years or older. If you sorted all the household incomes for in order, the median is the value in the middle. A drawback of this measure is that it weights all households the same (i.e. persons living alone have the same weight as four or five person families).

  • US Census Bureau’s Per Capita Income is the total income of all people 15 years or older reported in the Census divided by the total population in a geographic area. While income is not collected for people under 15 years old, those people are included in the denominator of per capita income. While median household income and per capita income measure different slices of the population, they use the same definition of income.

  • The Bureau of Economic Analysis’ (BEA) Per Capita Personal Income uses the same calculation as per capita income, but includes more sources of income than the Census Bureau. The Census Bureau counts money income before taxes and other deductions, while the BEA includes employer contributions to government employee retirement plans and to private health and pension funds, lumps-sum payments except those received as part of earnings, and certain in-kind transfer payments—such as Medicare, Medicaid, and food stamps.]

So, let’s take a look at where Oakland County ranks, keeping qualifiers and the different measures in mind. Among all 3,144 counties in the US, Oakland County ranks 200th using median household income (U.S. Census Bureau, 2013), 93rd using per capita income (U.S. Census Bureau, 2013), and 153rd using per capita personal income (BEA, 2013).

Among All Counties with Over 1 Million People Nationwide, Oakland County ranks:

  • 12th in the nation using the Census Bureau’s median household income

  • 10th in the nation using Census Bureau’s  per capita income

  • 12th when looking at the BEA’s per capita income

Among All Michigan Counties, Oakland County ranks # 1 using two out of three measures

  • Median household income: 2nd after Livingston County (65,594 vs. $72,359)

  • Per capita income: Oakland County is #1 at $36,458

  • Per capita personal income: Oakland County #1 at $57,035

Wealth vs. Income

Despite the clarity on income measures, Oakland County’s wealth continues to mystify us for one big reason: by looking at measures of income, we’re not measuring wealth. While the two are related—and generally work in tandem—the difference between the two is not simply technical.

So what exactly is wealth and how do we measure it? While income refers to the flow of resources, wealth is the value of the assets you own. Wealth is what you accumulate over time both in financial assets (savings and retirement) and non-financial assets (the value of your home and cars). Unlike income, which is generally spent on current consumption, wealth can be used for future consumption or as a form of security in times of economic hardship. Even a small amount of wealth can give families a means to avoid the vicious cycle of poverty and debt. Simply put, wealth translates into opportunity.

All of these complexities make wealth difficult to measure. Wealth is accumulated over a lifetime and may not reside in one place. Also, wealth can be stored in hundreds of types of ways (i.e. assets), all with varying levels of liquidity.

Wealth Data Sets

Here, we shine a brief spotlight on three of the most widely used and reliable sources for wealth data. A report from the U.S. Department of Health and Human Services provides a more in-depth analysis of the potential for asset research, especially for low-income households, including the limitations of the data sets and areas for improvement.4 Out of the 12 data sets identified in the report, here’s a condensed summary (in no particular order) of the top three:

  1. The Survey of Income and Program Participation (SIPP). SIPP is a household panel survey that has been administered by the U.S. Census Bureau since 1984. While SIPP collects information on a wide range of income and government program participation, it’s useful for measuring wealth as well. Its detailed information on financial and non-financial assets and liabilities allows researchers to calculate important wealth and well-being measures such as home equity, vehicle equity and net worth. The two- to five-year longitudinal panel survey design allows for an examination of changes in the nation’s economic well-being, including changes in asset holdings over time. Though the sample size varies, it has remained consistent around 50,000 households in the last three panels (2001, 2004, and 2008), allowing for detailed and high-quality data. While SIPP does a good job of capturing wealth and net worth of households, especially those that are low-income, the survey does not include retirement annuities or life insurance.

  2. Panel Study of Income Dynamics (PSID). Conducted by the University of Michigan’s Institute for Social Research, the PSID is a longitudinal survey that has been ongoing since 1968. It is a nationally representative sample of over 18,000 individuals living in 5,000 families in the United States that measures employment, income, wealth, expenditures, health, marriage, childbearing, child development, and education, among many other topics. Because the survey follows the same families over time, researchers can construct histories, trend studies and intergenerational analyses. Starting in 1984, the PSID included broad asset and liability questions, providing a good account of the major components of net worth (though from 1984 to 1999, these questions were only asked every five years). Of particular interest to researchers, the asset and liability data in the PSID are summarized to create net worth variables, with and without home equity. While the PSID does link its data to the U.S. Census data by Census tract, these files are restricted and require terms of usage and an administrative fee.

  3. Survey of Consumer Finances (SCF). Sponsored by the U.S. Federal Reserve Board of Governors, the SCF is a cross-sectional data set on the finances, wealth holding, pensions, and income of U.S. families. It has been administered every year since 1983. Unlike the SIPP and the PSID, which look at a broad range of demographic and income-related categories, the SCF focuses solely on assets and liabilities, and thus contains the most focused and detailed financial and nonfinancial tangible asset holdings information. However, its sample size is relatively small (6,492 in the most recent survey), and it only tracks net worth at a single point in time, thus making it difficult to study asset ownership over time.

Both income and wealth are important measures of economic well-being. So why does conflating the two matter? The most glaring reason is inequality: wealth inequality is much more extreme than income inequality. And while neither income nor wealth inequality have improved over the past 30 years, wealth inequality has gotten much worse—a topic to be explored in further posts.

1 “L. Brooks Patterson is Making Oakland County the Economic Engine of Michigan,”

2 Hopkins, Carol. “Oakland slips from Forbes list,” Oakland Press News, March 27, 2010,

3 For an in-depth analysis of the difference between BEA income and Census income, see here:

4 For more information on the datasets and their potential for asset research, see here: