Americans are happier in states that spend more on libraries, parks and highways

Public goods spending makes communities "more livable, with more amenities," Flavin said. "If roads are completed and kept up, so that people aren't stuck in traffic, they have more time to do things they enjoy doing. Large parks are social spaces -- and one clear finding of happiness studies is that people who are more socially connected tend to be happier."

Another benefit of spending money on public goods is that such amenities generally boost home values -- and "while higher property taxes generally accompany higher home values, it seems that the good outweighs the unfortunate part about having to pay higher taxes," Flavin said.

In his study, published in the journal Social Science Research, Flavin analyzed data on respondents' self-reported levels of happiness for 1976-2006 from the General Social Survey, a representative sample of Americans that monitors social characteristics and attitudes of Americans and is a project of the independent research organization NORC at the University of Chicago. Flavin also analyzed detailed government spending data for states from the U.S. Census Bureau for 1976-2006. Revenues to fund state public goods are raised from a combination of state taxes and transfers from the federal government to states, averaging 22.5 percent of total state revenues for that 30-year period.

"We can look at the city where people live, their neighborhoods, and see how public goods spending predicts happiness after taking other important factors, such as marital status, health, education and income, into account," Flavin said.

He also found that public goods spending has broad benefits across income, education, gender and race/ethnicity lines.

"Compared to a lot of the other government spending, public goods tend to be less controversial between liberals and conservatives, Democrats and Republicans, compared to poverty assistance or unemployment benefits, where there is definite disagreement between political parties," Flavin said. "I think there is less political conflict over public goods spending simply because if they government doesn't provide them, they won't be provided at all."

Flavin cautioned that there is not necessarily a cause-and-effect relationship between public goods and happiness.

"It could be that happier citizens self-select by moving to states that spend comparatively more on public goods," he said. "It also is possible that happier citizens support higher spending on public goods and elect state officials to deliver on that policy."

Because some spending for public goods comes from local government, Flavin hopes to do a study linking citizens to their local city instead of only to the state. And because living a happy and satisfying life is a nearly universal human goal, he predicts that better understanding of how policies concretely impact quality of life will receive increasing attention from researchers in the years to come.