It's become very clear that American companies have increased their focus on attracting and retaining talented women in the past few years in order to improve gender diversity. Companies have done everything from setting diversity targets and improving maternity leave benefits to launching bias training and flying nannies with new mothers. Many leadership experts, such as Harvard Business School Professor of Leadership John Kotter, have been on the record about the importance of this change needing to be driven from the top down. Yet evidence from over 10,000 employer reviews by women suggests that while the top down approach is necessary – it may not be sufficient to build a path to a truly gender diverse workplace.