Tackling the Wage Gap with Code

Hariri software team aids Boston Women’s Workforce Council


Hariri Institute director Azer Bestavros at a City Hall press conference on the Boston Women’s Workforce Council wage gap report earlier this month, flanked by Katie Conboy, Simmons College provost (from left), former Lt. Governor Evelyn Murphy, Boston Mayor Martin J. Walsh, and Eddie Ahmed, MassMutual Financial Group chief human resources officer. Photo by Cydney Scott.

Payroll data for 112,600 area employees reveals that women working in greater Boston make just 77 cents for every dollar a man earns, according to a new report from the Boston Women’s Workforce Council. That calculation was made possible by researchers at BU’s Rafik B. Hariri Institute for Computing and Computational Science & Engineering, who came up with a secure way for companies to report the data anonymously.

“This report is the first of its kind in the country, the first time actual wage data has been reported both anonymously and voluntarily,” Mayor Martin J. Walsh said in announcing the report. “This is a groundbreaking moment in tackling the gender gap.”

MaryRose Mazzola, executive director of the council, which is now housed at the Hariri Institute, says BU’s computing expertise “was absolutely crucial,” in enabling the report.

“What we were looking for didn’t exist yet, and we had to have Hariri essentially make it for us,” says Mazzola. “It’s the only way we can collect this unique data and make all the companies comfortable with participating.”

Payroll data is among the most closely guarded information at any company and is almost always hidden from the prying eyes of competitors without and employees within. Previous salary studies have depended on surveys that simply ask employees to volunteer their pay amount. But Hariri computer scientists created a secure way to collect data from company payrolls, then tested the technology with council lead sponsors State Street Corporation, MassMutual Financial Group, Vertex Pharmaceuticals, Putnam Investments, and Partners HealthCare. The results persuaded dozens more of the metro area’s largest employers to share salary data. In all, 69 companies, representing 11 percent of the area workforce and almost $11 billion in annual earnings, participated in the survey.

Employers “trusted us to take that data and make it anonymous and aggregate it so it can serve a common business and public purpose,” says council cochair Evelyn Murphy, a former Massachusetts lieutenant governor.

h_butoday_fullsizeoutput_6212MaryRose Mazzola, executive director of the Boston Women’s Workforce Council. Photo (right) by Mimi Segel of NECN.

“The institute is very proud of this piece of work, because we can build on it,” says Azer Bestavros, the Hariri Institute director and a College of Arts & Sciences computer science professor. “We feel it has legs to apply to lots of social science problems and other applications.”

The council is a public-private partnership between Boston City Hall and the business community, with the stated goal of making the city the best place for women to work. As of this week, 181 area employers have signed the council’s 100% Talent: The Boston Women’s Compact, indicating their commitment to end the gender wage gap. Many of them will report their salary data in the future. The council also disseminates best practices to companies and takes other steps to help and encourage companies to rectify the gap. The council will host representatives of the compact signers today at the Hariri Institute for a membership briefing on setting internal goals around gender, diversity, and equal pay at their companies. The panelists are Stephen Denny, Putnam Investments director of human resources and chief diversity officer, Cynthia Ring, Harvard Pilgrim Health Care chief human resources officer, and Beth Monaghan, InkHouse CEO.

A unique challenge

Bestavros was first asked to help the council back in 2014 by council member Katharine Lusk, BU Initiative on Cities (IoC) founding executive director, who was working with former Boston mayor Thomas Menino (Hon.’01) at the IoC, which he cofounded when he joined BU as a CAS professor of the practice. “The companies had pledged to help the mayor come up with quantitative measures of pay disparities…but the lawyers in the companies would not let this data leave their companies,” Bestavos says. “I had to convince them that we can build it. And within nine months we had our first prototype.”

The work was carried out by a team at the Hariri Institute’s Software & Application Innovation Lab (SAIL), a group of technologists and interns that puts programming expertise at the service of University faculty. The team, led by SAIL director Andrei Lapets (GRS’11), consisted of senior software engineer Frederick Jansen and Kyle Holzinger (CAS’16) and Eric Dunton (CAS’15), who were then students.

So how did they ensure that no company’s payroll data could ever be identified, while still coming up with solid numbers on what men earn and what women earn? Companies submit their encrypted data through their web browsers to a cloud-based service that runs an algorithm software platform created by the Hariri.

Bestavros explains:

“Say you have a number—1,000—and I have a number and a third person has a number. We want to add them to get a total, but we want to keep our numbers secret from each other. So, you divide your number randomly into three pieces that add up to 1,000. Say, -100, +500, and +600. There’s practically an infinite number of ways you can do this. And you give one piece to me and one piece to the other person, and keep one for yourself. And we are all going to do the same thing. Now each one of us has a share of each of the numbers. So we each add them. And then we add the results all together. And guess what, that’s the sum of the three numbers. Did anyone know anything about the others’ numbers? No. Your browser is not sending the number, it is sending shares that have been encrypted, a bunch of random bits as far as anybody else is concerned.”

Bestavros says the solution is a cryptographic construct, simple in concept, but making it work through a web browser was a unique challenge, with staff members in a wide range of companies working on all sorts of IT systems all over the area.

“We can apply the power of this technology to lots of other applications,” he says. For example, “You have homelessness in different parts of the city. We want to find out about homelessness, but no particular neighborhood wants to make its numbers known because real estate will suffer. This technology will solve that for you.” He says a number of people have already gotten in touch to explore possible uses.

Mazzola recently moved her office to the Hariri Institute to continue the collaboration between the council and the institute. “It’s a huge asset to us, having them to explore the possibilities of what we could use this data for,” she says. “For example, we’ve talked about breaking down the data by industry going forward.”

Bestavros says that by drilling down into results in coming years, they may be able to locate causes for wage disparities.

“We’re excited to continue the momentum with Boston University,” Walsh said at the announcement. “It just shows you Boston’s spirit of collaboration and working together.”

Author, Joel Brown can be reached at jbnbpt@bu.edu.