John Carrato, chief executive  of Alfred Benesch & Co., credits the Chicago engineer’s growth over the last five years to a decision to expand into new regions and service lines at a time when economic jolts and consolidation seem to be thinning the ranks of mid-size firms.

Benesch is one of 50 design firms, many mid-sized with 2013 revenue of between $19.4 million and and $122 million based on ENR Top Design Firms data, that now are being studied by a team of researchers and industry executives for their ability to outperform their peers, decade after decade.

What has emerged from the study are a set of characteristics shared by these successful firms, from efforts to broaden their range of work to succession planning to going above and beyond to retain top talent.

The study is the second phase of a University of Colorado-Boulder analysis whose results were first revealed in 2013. The research team includes Paul Chinowsky, professor of sustainable development; Rod Hoffman, chief executive of S&H Consulting; Jeff Holcomb, chief development officer for Larson Engineering; and business advisory consultant Gerry Salontai.

The research expands on the 2013 analysis that challenges claims that midsize design firms are slowly getting squeezed out by a few, globe-spanning giants. An article about the new study by Chinowski and Hoffman appeared in August in the Journal of Management in Engineering, published by the American Society of Civil Engineers.

To conduct the study, the researchers examined rankings in the ENR Top 500 Design Firms going back over a 25-year period to see what share of the overall market revenue different size firms accounted for. The researchers also measured the volatility of the companies and found that 7.9% of them were able to stay in the Top 500 the entire 25 years.

While the rate of relative growth of midsize firms falls short of the larger firms in the Top 500, the midsize firms continue to increase revenue. The mega-firms, the very biggest, increased their percentage of revenue from 10% in 1986 to 41% in 2011, taking some of that volume from the large and midsize firms. Large and midsize firms have lost 12% and 21% of their relative income since peaking in 1986.

And while the industry's mega-firms in the Top 500 have added an average $3.05 billion per company between 1986 and 2011, midsize firms have only been able to increase their revenue by an average of $16 million per company during the same period.

So while the relative growth falls short, causing some to speculate that the midsize firm faces extinction, the staying power also is evident.

The question is, "How do they do it?"

Focus on the Team

One of the qualities that keeps a mid-size engineering firm strong is a focus on the team rather than than the executives at the top, says one of the study researchers.

“The companies that tend to be the leaders also focus much more on long-term succession planning and leadership development,” notes Chinowsky, director of the Mortenson Center in Engineering for Developing Communities. “They keep the focus on the organization versus the owners. They really put the organization first instead of the leadership first.”

The most successful engineering firms first and foremost focus on what’s most important for a company and its employees, Hoffman said.

This list-topping characteristic for firm survival and success is a commitment “to investing in and developing staff, retaining talent and encouraging work sharing and collaboration,” the authors say.  Other attributes include “smart diversification,” and delivering financial performance, Hoffman said.

Yet the study also found that it wasn’t enough just to have a list of laudable goals.

While companies often talk about doing these things, many still don’t do them or are inconsistent in execution,  says Salontai, chief executive of Salontai Consulting Group.

In recent discussions with two studied firms, Salontai found some interesting differences.

The first company made it a routine practice for its top executives to spend “face time” with key clients. The second firm, when asked if the company’s leaders spent time with clients, responded with a quick, “Oh yeah, we have that program,” he recalled.