The term “efficiency gap” generates a buzz among those who want the federal courts to scrap partisan electoral gerrymandering.

But an exchange during last week’s joint meeting of state House and Senate redistricting committees suggests some confusion about the gap. That confusion extends to its usefulness in helping lawmakers draw new electoral maps.

The term cropped up as Sen. Ben Clark, D-Hoke, queried House redistricting leader Rep. David Lewis, R-Harnett. Clark sought details about technology that will be available to voters during planned public hearings on new legislative election maps.

“Will it be able to do things such as perform efficiency-gap calculations … for individuals to actually determine the extent of partisan … gerrymandering within the maps, or lack thereof?” Clark asked.

“I don’t know, sir,” Lewis responded. “I know that the data that is produced allows individual members to analyze it in the way that they see fit.”

It’s not clear whether either legislator realized that it would be impossible to conduct an efficiency-gap analysis for election maps that have not been used for an actual election. A brief review of the efficiency gap explains why.

Syracuse University law professor Tara Helfman offers a brief description. For the two major political parties, “a ‘wasted vote’ is a vote cast for a losing candidate or a winning candidate in excess of a bare majority.” The efficiency gap “divides the difference between the respective parties’ wasted votes by the total number of votes cast.”

Put another way, a political party that secures huge victory margins in the elections it wins but loses a majority of its elections sees less efficiency. A party with smaller district-by-district victory margins but more overall wins sees greater efficiency. The gap between the two parties represents the efficiency gap.

Calculating that gap might sound like a good problem to throw at public school math students. But efficiency gaps could end up having a much larger impact. Those gaps could help influence the future of American elections.

As Helfman notes, plaintiffs in a Wisconsin redistricting lawsuit consider the efficiency gap “the holy grail of political law.” Advocates consider it “a ‘judicially discernible and manageable standard’ against which to assess the constitutionality of a redistricting plan.”

In other words, the objective, measured efficiency gap could give judges cover to strike down election maps as overly partisan. A federal court in Wisconsin already has accepted the idea. The U.S. Supreme Court is scheduled to address the issue this fall.

Meanwhile, the League of Women Voters is challenging North Carolina’s 2016 congressional election maps using the same efficiency-gap argument. If the nation’s highest court agrees that an overly large gap signals an unconstitutional partisan gerrymander, it’s likely that mapmakers on Jones Street will head back to the drawing board.

There are good reasons to hope that justices will reject the efficiency-gap standard. “The Constitution enumerates many rights, but the right to an equal number of wasted votes is not among them,” Helfman notes.

To enshrine the efficiency gap into constitutional law would step beyond the courts’ proper role. “Short of judicial preference, it is not clear why the ‘efficiency gap’ is more principled, rational, and reasoned than other possible approaches to political apportionment,” Helfman explains.

Problems extend beyond the efficiency gap’s application as a legal standard. Its basic premise is flawed at best.

Efficiency-gap analysis accepts as fact the notion that the two major political parties exercise complete control over competing blocs of votes. Any votes that do not meet the goal of maximizing one party’s electoral advantage are “wasted.”

That’s not how elections work.

In actual elections, voters control their votes. While they might tend to vote for one major party or the other, their approach toward any particular election varies based on multiple interacting factors. What major national and statewide issues are driving voters to the polls? Who are the candidates running in a particular race? Is it an open seat? What other issues are on the ballot? Is it cold or rainy on Election Day?

The efficiency gap takes no account of these human factors. Its mathematical formula cannot account for a candidate who successfully attracts bipartisan support. The number crunching says nothing about an incumbent who’s so popular that credible challengers step aside. There’s nothing in the calculation to adjust for major national political swings toward or against a political party.

And, back to our original topic, the efficiency gap tells us nothing useful about election maps that never have been used. New election districts will attract new candidates. Until voters cast actual votes in those new districts, it’s impossible to calculate the gap.

Electoral map makers can — and do — use historical election data to guide their decisions. They can estimate fairly well which political party is likely to win a race in a particular district.

But they can’t guarantee the future. They can’t pinpoint how factors such as the interplay of state and national political issues, likely incumbents, and prospective challengers will affect each district’s victory margin.

In efficiency-gap terms, they can’t say how the voters of tomorrow will cast their “wasted votes.” To attempt to do so would amount to a waste of time.

Mitch Kokai is senior political analyst for the John Locke Foundation.