(Bill Pugliano/Getty)Before becoming the CEO of General Motors last year, Mary Barra's GM career spanned 33 years.
Despite living and breathing the company most of her life, she's been able to take its culture in a new direction and guide it to a record sales year in 2014 despite a massive recall disaster.
At the 2015 Catalyst Awards, honoring progressive gender initiatives in American corporations, Barra told Catalyst president and CEO Deborah Gillis that "the smallest biggest change" she's made at GM involved changing the dress code.
It's a fitting representation of Barra's management philosophy, which is focused on handing power to managers and keeping GM as lean as possible.
In 2009, Barra was appointed vice president of global human resources as GM began its attempt to recover after filing for bankruptcy. She felt that GM was mired in a long tradition of bureaucracy, and the debate over the company's dress code was a perfect example.
The HR team developed an extensive dress code meant to encompass the needs of a variety of workers, from engineers to salespeople. It included specifics, Barra explained to Gillis, such as, "You can't wear T-shirts that have words on them that could be misinterpreted." Barra wondered what this could even mean.
She was reminded of about 15 years earlier, when she worked on the team that developed a new company code of conduct. One of the team's senior leaders had written a draft that was instructive and detail-rich. On second look, he determined that employees would find it patronizing and so he scrapped the entire thing and started over. "It was a very impactful statement," Barra said.
So when confronted with a similar situation, she decided to ditch a 10-page treatise on clothing and made it simply, "Dress appropriately."
Of course, there was some backlash from managers.
For example, a high-ranking manager sent her an email saying that the new system prompted his team to start wearing jeans, which embarrassed him when it was time to take them to important meetings. Barra said she gave him a call.
"I said, 'Well have you talked to your team about this?' He said, 'No.' I said, 'Well, why don't you at your next team meeting tell them what you're worried about and see what they say?'"
Two weeks later she heard from him again. He had the discussion with his employees and they decided they could wear jeans in the office as long as they kept a pair of dress pants in their desk drawer for impromptu meetings. He was overjoyed, Barra said.
Similarly, when she received a complaint from a manager that one of that person's female employees was wearing clothing that was a bit too skimpy, Barra said there was no rule she could write that could change that behavior. It was up to the manager to act as a leader.
Instead of having a culture where she developed a rule and then needed to continually explain it, "I want them to take ownership of the rules and say, 'You're accountable to lead your team,'" she said.
As VP of global HR, Barra shrank the requirement for HR reports by 90%, Bloomberg reported in 2013. As senior vice president of global product development and then CEO, she focused on simplifying the manufacturing process of GM's vehicles.
She's even embraced last year's recall crisis as a means of further reforming the corporate culture, she told Fortune last year, cutting decision-making by committees and encouraging a system of inter-office communication and transparency.
It comes down to what motivated her to change the dress code. That decision is "a window into things that we attacked early to empower the managers," she said at the Catalyst event. "And I say we've seized that opportunity to really drive a significant culture change within the company."
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