The U.S. Census Department announced yesterday that in 2008, 46.3 million Americans did not have health insurance, a “not significant” increase from the 45.7 million uninsured the year before. But dig a little deeper into the survey—and understand its limitations—and you’ll find that the 2009 Current Population Survey (CPS) actually provides a compelling snapshot of the country in recession. Besides the new data on the uninsured, the survey also includes information on household income (down 3.6% between 2007 and 2008) and the poverty rate (13.2%, up from 12.5% in 2007).

Taking a closer look at the data also reveals which populations are most likely to be uninsured and where the need for reform is felt most strongly. The Census survey finds that 1.6 million more adults lost their health coverage between 2007 and 2008. The opposite is true for children; expansions in CHIP and also increases in federal matching funds for Medicaid coverage for kids have left fewer vulnerable and uninsured.

“The good news for kids is that Medicaid and CHIP are absorbing some of the uninsured and that’s pretty amazing given many states’ economic problems,” says Genevieve Kenney, a Senior Fellow and health economist at the Urban Institute. But, she goes on to say, “For adults, the public programs aren’t really there to catch them. This reflects real gaps in the safety net.”

Other key trends: fewer people have employer-based insurance (a drop of nearly 1 million), fewer people are covered by private health insurance  (66.7 percent in 2008 — down from 67.5 percent in 2007) and more folks are relying on government health insurance programs (29 percent in 2008, from 27.8 percent in 2007) for coverage.

The CPS survey, just like every other survey that attempts to count the uninsured, also drives home the fact  most of the uninsured are low income and are likely to remain that way because they can’t afford to buy insurance. Hispanics and young people continue to have the highest rates of uninsurance, but, according to Kenney, there’s also a troubling rise in the number of older adults (over 55) who have lost health coverage.

How accurate are the Census figures on the uninsured? Trying to determine how many uninsured Americans there are is a wiggly science—there are four national surveys that attempt to determine this number and the range in 2002, for example, was from 43.3 million (CPS) down to 20.4 million from the Survey of Income and Program Participation—a survey also conducted by the Census Bureau. If you’re interested in reading more about the difficulties inherent in collecting this information and the kinds of hoops health economists jump through to make sense of it, here’s a recent take on it.

In two weeks, the Census will release the results of a brand new survey, which according to Michael O’Grady a Senior Fellow at the National Opinion Research Center (NORC) at the University of Chicago, writing on the Health Affairs blog, will add to the data pool and could provide a more accurate reading of how many Americans, at a particular point in time, are without coverage.

“The American Community Survey, successor to the Census ‘long form,’ will report detailed health insurance coverage for the first time this fall. The sample size of roughly three million people is more than ten times the size of the other major surveys. Analysts hope that this new source will resolve many of the issues around the estimates of the uninsured and not make them more confusing than they already are.”

Besides the national surveys, which by design are at least a year behind in determining how many Americans are uninsured, the health insurance industry does some estimates of their own. In fact, yesterday in an article in Bloomberg, an analyst from Sanford Bernstein & Co. who follows the large health insurers UnitedHealth and WellPoint said that the number of uninsured was likely to hit 50 million as unemployment jumped in recent months.

President Obama quoted yet another set of figures, (obtained by the administration from the polling firm Gallup but not yet public) in a speech he gave yesterday in front of the American Nurses Association:

"And we know from more up-to-date surveys that since the recession intensified last September, the situation has grown worse," the president went on to say. "Over the last 12 months, it's estimated that the ranks of the uninsured have swelled by nearly six million people — that's 17,000 men and women every single day, and we know that during this period of time, the number of adults who get their coverage at the workplace has dropped by eight million people."

In the end, how important is it that we know the exact number of people who are uninsured in America? Clearly, it’s impossible to calculate the true cost of reform if the government doesn’t know how many people will qualify for subsidies or enroll in public programs. That happened in Massachusetts where Commonwealth Care—the state-sponsored program for lower income residents—saw 30,000 more enrollees than expected in 2008, driving up costs for the program and forcing cutbacks.

When making projections about costs of reform, health economists take the figures from CPS and other national surveys and match them with state data, Medicaid and Medicare data and other factors. There’s a lot of work that goes into making these determinations that goes on away from the public eye.

But from an overall policy point of view, all current indicators point to the fact that our current health care system is at the breaking point. We can see that too many people have lost coverage, and that many of these folks are facing severe economic stress because of it. We also know that there are an awful lot of people who are not getting the care they need—waiting until they are gravely ill before seeking help and putting off important preventive care and services.

Newer data just confirms the obvious; each day more people are losing their jobs and along with that, their employer-sponsored coverage. Those that are able to buy health insurance through the individual or small-group market are often under-insured; facing huge deductibles, lapses in coverage and large co-pays that leave them economically stressed and unable to access comprehensive care.

The American Public Health Association released a statement yesterday that gets it just right:

“Disturbingly, the uninsured numbers from the U.S. Census Bureau represent the tip of the problem. There are another 25 million underinsured people who also receive inadequate access to care and are at risk of many of the same outcomes as those with no coverage at all.

“This is unacceptable for a rich nation; it is unacceptable for a humane nation; it is unacceptable for a just nation.

“All eyes are on Congress. Once and for all, let's roll up our sleeves, leave our ideologies at the door and craft a bill based on sound policy. We must pass comprehensive health reform legislation that ensures competition through a public option, provides access for all with universal coverage and redirects the emphasis of our health system with a renewed focus on prevention.”