Lacking a mentor to guide them through the corporate gauntlet, blacks will leave a company often because they cannot move horizontally to gain the broad experiences necessary to rise through the ranks.

"Folks of color don't leave because of title and money," Poriotis said. "They want to expand their portfolio and they can't in the company. The glass walls are more impenetrable than the glass ceiling."
—Christopher Mele and Andrea Rubin, "Plenty of room at the top," Journal News (Westchester County, NY), March 24, 2002

A systematic review of development needs is particularly critical for high potential mid-level women managers who are more likely to lack balance in their corporate experience because they have been concentrated in staff activities. If this is not done, American companies face the potential of wasting a generation of female talent that is in the pipeline for senior management but is not receiving the kind of balance and breadth of experience that is needed by corporations today. . . . These are the women for whom it is critical to break down the glass wall.
—"On the Line," Catalyst, 1992