Betsey Stevenson is chief economist of the Department of Labor.

Nearly all Americans identify as either working or middle class. Only 3 percent consider themselves to be upper class and slightly more — 5 percent — identify as lower class. These patterns have been stable over the past four decades in which the General Social Survey has asked about social class; they hold whether the economy is booming or busting.

Years of economic setbacks have not fundamentally changed what the middle class wants out of life.

So what defines the middle class? Not income. Your current income is a poor predictor of the social class with which you identify. For example, among families with incomes between $60,000 and $75,000, roughly equal numbers considered themselves working class and middle class, with 2 percent reporting to be lower class and 1 percent upper class.

Current income is a poor predictor of social class because income changes throughout our lives, while social class is more enduring. Economists would prefer that we knew your lifetime average income as we suspect that this would be more highly correlated with the social class with which you identify. But even with a better measure of one’s lifetime income I suspect that we would still find that income alone doesn’t predict social class.

This is why the White House’s Middle Class Task Force defines middle class families by their aspirations, more than their income. Middle class families share an aspiration to own a home and car, to send their kids to college, and to take occasional family vacations, all while maintaining health and retirement security. This understanding of the middle class also helps explain why so many people identify with this group so consistently through time.

In our current economic climate many people have faced temporary setbacks. Unemployment is too high, home values have declined, and many have seen their savings shrink. But this hasn’t fundamentally changed the middle class. Their aspirations remain the same.

While the middle class has been hit particularly hard by this recent recession, the assault on the middle class has been occurring for decades. The middle, working, and lower classes have received little of the income gains over the past several decades. Meanwhile, the costs of housing, education and health care have all risen faster than incomes.

Supporting the middle class requires a multi-pronged approach. Jobs, education, housing, health care and a secure retirement must be within reach of most Americans.

This is why the Middle Class Task Force is a major initiative of the Obama administration. To touch on just a few examples: Labor Secretary Hilda Solis has made it her mission to support good jobs and to ensure that workers are able to access the training necessary to land these jobs. Students and their parents must be able to pay for a college education, and financial concerns shouldn’t distract students from completing their degrees. This is why reforming student lending and increasing Pell Grants has been an administration priority.

More recently, the tax bill extended a tax credit to help more than eight million students and their families afford the cost of college. We are also making an unprecedented investment in community colleges, including increasing partnerships with businesses to ensure that these programs are providing training for the jobs that employers need to fill — now and in the future.