Ropes & Gray LLP’s Chicago office managing partner Asheesh Goel is hired to give answers.

But he wrestled with this question, posed to him by a private equity client: “Without spending a year and $20 million, how can I assess the risk of bribery and corruption at the 60 different companies in my portfolio?”

“I thought, ‘Huh, that’s a good question,’” said Goel, the 41-year-old co-chair of Ropes & Gray’s global anti-corruption and international risk practice.

So he went where every great innovation is born: the back of an envelope.

What he scribbled out is an example of the “organic entrepreneurship” that Goel said Ropes & Gray thrives off of — which is important, considering it doesn’t use the traditional compensation carrot known as origination credit.

It also highlights the firm’s “hunting in packs” approach to staffing projects and gaining new clients.

The product from that envelope sketch is known as the Ropes & Gray Anti-Corruption Risk Matrix. It won an award from the Financial Times for innovation. More than 25 private equity clients have hired the firm because of it, and it has brought in more than $20 million in fees.

The answer Goel found to his client’s question is somewhat complex, but worth understanding.

First, sort every company’s revenue by the country it originates from. Then multiply that by the country’s “corruption perceptions index” — a ranking of countries from least corrupt (Denmark) to most (Somalia). Then take into account what percentage of that company the private equity firm owns.

For brevity’s sake, do a couple more calculations.

What you end up with is a weighted average for the chances that you, the general counsel of a private equity company, will be getting a phone call from U.S. authorities about the Foreign Corrupt Practices Act, which last year lightened corporate coffers by $731 million in fines.

The benefits of the matrix Goel dreamed up on an envelope currently awaiting placement on his office’s wall are simple: Know where your weaknesses are. Start preventing that phone call to Goel.

Talk about “weighted averages” to most attorneys and, as Goel said, “their eyes glaze over.” But it took advantage of his undergraduate degree in finance.

“It was natural entrepreneurship,” Goel said. “It was not, ‘Asheesh, if you don’t come up with a risk matrix, we’re going to fire (you).’ It was not that. It was more something that organically bubbled up from a question the client asked me.”

And what happened after he came up with the idea drew from the non-lawyer skills of other associates and partners alike — an example of the firm’s “hunting in packs” mentality.

Goel sat down with an associate who has an art background. She sketched out how the companies should be plotted on a graph to depict their risks. Each dot represents a portfolio company. As the dots move farther up and to the right from the origin, their risk of corruption increases.

Then he brought the idea to another young lawyer who is a former Deloitte consultant and previously wrote computer code at IBM. He turned the plotting system into a Web-based product that relies on some simple client inputs — mostly where their revenue comes from.

Once the companies knew where the risk was, it created a sort of virtuous cycle for Ropes & Gray lawyers. First, they were hired to find it. Then hired to investigate it. Then hired to fix the problems.

“So this little piece of trying to be creative about solving a client frustration has led to 150 engagements,” Goel said. “That’s the benefit of natural entrepreneurship.”