Marcelo Paiva, pictured on Capitol Hill, is using his master’s in public policy degree to consult for an environmental policy firm.

Marcelo Paiva doesn’t want to just write public policy. He wants to understand the research and analysis that helps policymakers decide to address a particular problem or fund a certain program. So while getting his master’s in public policy at American University, Paiva loaded up on quantitative analysis courses, including classes in micro and macro economics, statistics and finance. Now, he has the tools to measure the effectiveness of a policy and help determine if a program’s cost is worth its results.

“Everyone really wants to know that their money is being invested wisely,” says Paiva, 24, who recently completed his degree and is doing consulting work for a research firm focused on environmental policy.

A great idea is one thing. But do the numbers show that it’s needed or that it will be worth the cost? And how have similar approaches fared in the past? Those are the kinds of questions that drive the public-policy decision-making process these days.

Governments, nonprofits and other organizations increasingly want data and statistics to back up their decisions.

“It’s coming from the top; Congress wants to see it, the president wants to see it,” says Sheena McConnell, an associate director and senior fellow in the D.C. office of Mathematica Policy Research, which studies and analyzes the effectiveness of policies and programs.

“It’s not just let’s continue funding this program or doing this policy,” McConnell says. “They want to know that it works.”

To that end, many employers in the public policy field are looking to hire people who can analyze complex sets of data and use the results to craft effective policies in such areas as education, crime prevention and international development.

Taking quantitative courses ­has long been a requirement in most master’s in public policy (MPP) programs. But these days, many students choose to go well beyond the core requirements for quant classes. Even the schools themselves are pushing students to gain more of those skills, citing the growing need for them in today’s job market.

“I think we need more quantitative skills in MPP programs; we could be pushed harder to be better at quantitative reasoning,” Paiva says.

The trend is being driven, in part, by the move for accountability and transparency in the public and private sectors, says Sandra O. Archibald, president of the Association for Public Policy Analysis & Management.

“Students are in so much demand if they have that skill set,” says Archibald, who is also dean of the Evans School of Public Affairs at the University of Washington in Seattle.

Mathematica’s McConnell says candidates with master’s degrees in public policy need to have strong quantitative skills when applying for positions at her company.

“When they join us, they don’t need to be able to do a complex statistical analysis,” McConnell says. “But they need to be able to understand one when presented it.”

And since a statistical model is only as good as the data it’s based on, public policy grads must be able to evaluate the quality of the data itself. Separating “good” data from “bad” is a vital skill for any public policy student whether they’re doing their own research or using someone else’s findings. They must assess how the data was produced and if there could be any potential problems with the research methods used or other factors.

Taking quantitative classes “makes them better consumers of the information they come across,” says Carolyn J. Hill, associate dean for academic affairs at Georgetown University’s Public Policy Institute.

But experts point out that strong quantitative skills don’t mean anything if students can’t put data into some kind of context, which is where qualitative analysis comes into play. An understanding of human behavior and how people make decisions is important when crafting effective policy.

“Numerical analysis only goes so far,” says Todd Olmstead, assistant professor of public policy at George Mason University. “You can figure out how many lives guardrails save, but that isn’t going to tell you whether or not you should spend money on [them].”

Many public policy students choose areas of expertise. Some of those, such as health care, might rely heavily on data. But other areas depend on qualitative skills just as much as quantitative acumen.

Ernest Wong, who earned a master’s in public policy from George Mason University in May with a focus on national security, has found this to be the case. In his experience, the numbers alone can’t tell you how best to protect the country, and it takes more than a computer program to understand the reasons behind any threats.

“Even if you’re lucky enough to have good data and find robust correlations, determining whether they qualify as causation requires human judgment,” says Wong, 26, who recently completed an internship with the federal government.

But other students, including Paiva, believe that their dexterity with data is what will get them jobs and help them create new policy that’s both efficient and effective.

“The signals I’ve been getting from the job market are that it’s important to have that extra edge,” Paiva says. “People won’t hire you because you know their organizational culture; they really want to know where their dollar is going and if it’s having the impact intended.”