It found that a hypothetical middle-class Philadelphia family in 2012 paid 12.9 percent of its income in state and local wage, real estate, and sales taxes - its tax burden. In 2000, that figure was 13.5 percent.
By contrast, the average tax burden in the Pennsylvania suburbs increased from 9.8 percent to 12.2 percent in the same period - leaving suburbanites only slightly better off than residents of the city. In South Jersey, the rate increased from 9.9 percent in 2000 to 11.3 percent in 2011, the most recent available figure.
Given the upward trend in suburban taxes, "I'm not really surprised at the findings," said Scott Drenkard, economist at the National Tax Foundation, a Washington research group. "I think the story overall is an accurate one."
The upshot of the narrowing gap in tax burdens, the Pew report said, is that the city has erased some of the competitive tax advantages long enjoyed by its neighbors.
The study, however, was confined to taxes, and did not consider issues such as business levies, other fees, or the quality of municipal services and schools. "The analysis also does not reflect whether residents are getting their money's worth," the report said.
The tax-burden figures were calculated for a family of four making $60,000 annually and living in a house worth $186,000 - a standard income-to-home value spread. But that is hardly a one-size-fits-all model.
"Our findings are not reflective of real families," said Thomas Ginsberg, the report's author.
For the model family, Pew attempted to measure the percentage of income that Philadelphians and suburbanites spent on property, wage, and sales taxes in 2000 and 2012.
Why did the gap between the city and the suburbs tighten? Suburban real estate taxes have risen more robustly than the city's, and while some towns have added earned-income taxes or raised rates, the city lowered its wage tax from 4.6 percent in 2000 to 3.9 percent in 2012. The wage tax remains the source of the bulk of the city's tax revenues.
Philadelphia residents pay wildly different property-tax rates, as a result of a broken assessment system. But on average, the city's effective tax rate - the annual bill as a percentage of home value - is about 1.2 percent, compared with 2.3 percent in the suburban towns.
The owner of the $186,000 house in the suburbs would pay $2,000 more annually than the city counterpart.
The study found that the heftiest tax burdens are borne by suburban commuters into the city who pay higher property taxes where they live, then get hit up by Philadelphia's wage tax.
However, the workforce commuting to the city represents a dwindling minority in the neighboring counties. An analysis by the Delaware Valley Regional Planning Commission puts that number at about 11 percent, roughly half what it was in 1970.
The average suburban-burden number got an upward boost from property-tax rates in eastern Delaware County, which are among the highest in the country. The list included towns such as Darby Borough and Collingdale, where $186,000 homes are scarce.
Since the Pew results were not weighted by population, Darby would carry the same value as Lower Merion Township, which is about five times its size.
Working to hold down the suburban burden figure would be the inclusion of Pine Valley and Tavistock, which are essentially incorporated golf courses. Their burden figures were among the region's lowest.
The results would have been more precise if weighted, said Forrest Huffman, real estate and finance professor at Temple University. He added, however, that the sample size probably was large enough to correct for outliers.
Ginsberg said economists who reviewed the report found the methodology sound. They concurred with the basic conclusion that the tax advantages of living in the suburbs vs. the city aren't what they used to be.
Contact Anthony R. Wood at 610-313-8210 or firstname.lastname@example.org.