Like many, many other Americans, Alan Krueger was frustrated by his jury-duty experience. The Princeton economist showed up to court in Mercer County, New Jersey only to be told after an hour’s wait he was free to go home for the day: the only case scheduled was settled out of court. He could still be called in on the following days. A “mad frenzy” of the hundred-plus potential jurors ensued when they all tried to get on a bus back to the parking lot.

The former chairman of President Obama’s Council of Economic Advisers was bugged by this inefficient use of his time. He took to Twitter to vent, but also to suggest a solution, as any self-respecting, award-winning economist who held multiple positions in the US government would do:

“It seems to me that this is something that needs to be done scientifically, taking a ‘Moneyball’ approach to how big a group needs to be called in to form a jury,” he said, summing up his idea in an interview with Quartz.

There’s a lot of subtraction to get to 12

It’s a problem US courts are trying to fix. There is even a metric courts use called the “juror utilization rate” to measure just how many potential jurors are called in unnecessarily. A notorious example of inefficiency is the juror utilization rate from the early 2000s in New York: 82% of those summoned were never selected for trial.

To get 12 citizen jurors, you need to call in many more people. Potential jurors can be eliminated due to scheduling conflicts, economic hardship, bias, or—within limits established by states—simply because the defense attorney or prosecutor thinks they will be unfavorable to their side. In most courts, it’s reasonable to call in between 45 and 60 people, says Paula Agor-Hannaford from the Center for Jury Studies at the Virginia-based National Center for State Courts. That number can rise dramatically if a case is particularly sensitive or controversial.

Hannaford, who advises courts on how to be more efficient, said that in some jurisdictions calling in dozens of unnecessary jurors remains “a very big problem.” Others have figured it out, but there’s no visible improvement across the board.

“It goes in waves. Some courts get really good, and then they get sloppy again,” she says. ”Some of these practices don’t get institutionalized well.”

Some courts already do something akin to what Krueger suggests: “In larger urban courts where you have multiple trials going forward on any given day, you can—and in fact, many of the courts actually do—play the numbers. You have the jury managers on the day before going ‘OK, we have 14 cases that are scheduled for trial, four are going to drop out, so we only need jurors for ten,’” Hannaford said.

In smaller or rural courts this may be harder, simply because the juror pools are smaller, and there are fewer trials.

Is an empty pool worse than one that overflows?

Krueger, of course, reasons along economic lines. When a court miscalculates, and unnecessarily calls in dozens of people who lose sometimes days of work, the jurors—and society at large—unfairly cover most of the costs. “You’re making the juror pool bear all the risk,” he says.

Perhaps the lawyers, defendants and judges should have to wait every once in a while, because they don’t have enough jurors. “Is it the end of the world?” Krueger asks.

Hannaford says that if there’s even the slimmest possibility a case will go to trial, “you have to have the jurors there.” Because of the costs involved in rescheduling, courts will play it safe. Jury managers, the court officials responsible for calling jurors in, are risk averse, she says. They are responsible to the judges, so they will always try to have enough jurors to choose from.

What’s more, she says officials don’t particularly care about costs to the jurors, such as lost wages: “Judges and attorneys are typically only looking at what the juror fees are.” In Krueger’s case the payment was only $5 a day. If 100 people are called in at that rate, for the court it’s “definitely worth it to have [paid out] $500 for a case that otherwise wouldn’t have gone forward and probably would’ve cost $5,000 to reschedule,” Hannaford says, although she thinks courts should consider societal costs as well.

Communication is key

Hannaford says generally, it’s predictable whether a felony or serious civil case will go to trial. “The prosecutor and the attorney know what’s going to happen. It often doesn’t get communicated to the court,” she says. Her organization tries to impress on judges the need to work very closely with both sides.

To avoid last-minute changes, some courts have a deadline for plea-bargain deals—the day or week before the trial. If a defendant seeks a deal after the set date, a judge won’t approve a reduced sentence. “Courts that do that—and mean it—have much, much better results of not bringing in jurors unnecessarily,” Hannaford said.

This is important, because jury duty shouldn’t be seen a useless nuisance, but a vital civic obligation. Krueger hypothesizes that if fewer people got called in only to wait all day or get sent back home having had no input in the system, Americans would generally be more willing to participate in jury duty.