Imagine you're the sustainability director at your company, responsible for developing and implementing core initiatives across your organization. What's more important to your success: your knowledge and expertise around sustainability issues, or your interpersonal skills?

If you're like most sustainability professionals entering the field, you might say subject matter expertise. But once those pros are on the job, they say something very different, according to a new study from Vox Global, Net Impact UC Berkeley Undergrad, and the Weinreb Group.

The results were revealing:

Prior to taking the job, the majority (78 percent) said they had assumed that subject matter expertise would be the most important predictor of success. Once on the job, however, all respondents (100 percent) said interpersonal skills proved to be most critical.

Subject mastery is crucial, but sustainability leaders said they had to first sell the concept of sustainability-and sell themselves-before focusing on the content. To secure buy-in, sustainability leaders, like other senior positions, also had to balance subject matter expertise with business acumen. The ability to communicate the business case for sustainability in a language that resonates up, down and across an organization was viewed as crucial to achieving the ultimate objectives.

Download Making the Pitch from Vox Global

This qualitative study very nicely complements our own recent research around workers' attitudes about impact work. While our Talent Report: What Workers Want in 2012 explores students' and employees' desire for impact work, Making the Pitch gives us a thoughtful look into what it's like to actually do such work. For more insights on making environmental or social change within your job, check out Corporate Careers That Make a Difference, our guide released in 2010.