RALEIGH — It’s been a hot public policy issue for decades: are we better off with fewer local governments, delivering services more efficiently with less duplication, or are we better off with more numerous and competing localities?

Although applicable to a wide variety of local functions, from law enforcement to growth management, the merger debate has been at its most spirited when the topic is education. North Carolina, like most states, operated its public schools for years with administration spread over counties, cities, even small towns. The reasons were varied. Some of it was tradition. Some of it was the parochial interests of existing boards and power structures. Some of it was a desire by smaller communities not to get swallowed up by larger ones. And some of it reflected a deeply felt belief that government was best when it was as close as possible to the people — the implication being that larger units of government would become more remote, more bureaucratic, and less effective.

And then there was race. While racism and segregation existed in small and large districts alike, there was a particularly difficult challenge in communities where a mostly white county system surrounded one or more majority black city districts. Merger seemed to be a necessary part of desegregation — but it also threatened to deprive experienced administrators and school-board members of opportunities for leadership in their communities, creating more distance between the rulers and the ruled.

Throughout the past half-decade, there has been a steady decline in the number of school districts across the United States. There have also been numerous attempts to quantify the impact of these mergers on the cost and output of education. Unfortunately, whether the studies were perfunctory or carefully designed, the results have rarely “settled” the issue. Advocates see what they want to see. Opponents do the same.

There is a great example of this dynamic in Sunday’s News & Record of Greensboro. The paper’s excellent education reporter, Bruce Buchanan, examined the Guiford school merger after 10 years — and found evidence that supports both sides of this not-long-forgotten controversy in North Carolina’s third-largest school district.

Did the merger save taxpayers some money? There may have been some administrative savings, but the overall trend line on cost seems to be up. Did the merger alleviate longstanding racial disparities and bring more integrated schools? Yes and no, respectively. Scores for black students have improved since the merger, but Buchanan reported that Guilford schools are “more segregated today than they were 10 years ago.” Are Guilford residents satisfied with the results of the merger? Depends on whom you ask. A bond issue just after the merger failed miserably, but a more recent one passed. Little political rhetoric today reflects the merger issue itself, but many of the same debates about priorities, construction, taxes, and student assignment continue.

Evaluating the impact of mergers on student performance is especially tricky because there are so many different factors that can affect the outcome. For example, Buchanan noted that overall test scores have risen in Guilford over the past decade. But that’s true for North Carolina as a whole — and despite lots of confident assertions to the contrary, no one really has a persuasive explanation as to why. The scores were rising before the state legislature raised teacher pay, created Smart Start, created charter schools, and enacted the ABCs program linking tests, rewards, and punishments. Scores kept rising after these measures were enacted in the mid-1990s at pretty much the same rate as before. That there were also some high-profile district mergers during the 1990s, including Guilford, is just one more trend to factor into this already confusing equation.

For my part, I have long been persuaded that school-district merger, while possibly justified in areas of very low populations, was taken too far decades ago. The result has been monstrous districts, some with more than 100,000 students. All other things being equal, I think that the available research suggests that districts of such size are unlikely to deliver the best educational bang for the buck. One drawback to my argument is that you have to take the “all other things being equal” stipulation very seriously, since the second-largest district in the state — Wake — is also one of the best-performing districts.

It is a complex problem and one unlikely to be resolved anytime soon. It’s been 10 years since the Guilford merger, and the piture remains stubbornly murky.

Hood is president of the John Locke Foundation and publisher of Carolina Journal.