Using the Leadership Versatility Index they paired females with males based on comparable age and managerial experience. They looked for gender bias in the way men and women rated their own sex as well as the opposite sex. Their studies were conducted in six companies in three industries on three continents.  

• Women and men are rated similarly by bosses of both genders, as well as peers and subordinates. 
• The strongest evidence for bias comes from women and not men. Female raters rate women more harshly than do male raters. Self ratings are the harshest of all - women leaders are particularly self-critical. 
• Women are more likely to be rated as "too much" on "Forceful behaviors" as controlling, directive, outspoken, and demanding.
• Women are likely to be rated "too little" on "Enabling behaviors" such as hands-off, empowering, and receptive to push back. 
• Men are more likely to be rated as "too much" on "Hands-off."
• Women are rated better ("the right amount") on results-orientation, tactical, attention to detail, and follow-through compared to men who are more often rated "too little" on these "Operational behaviors." 
• Men are rated better on "Strategic behaviors" whereas women tend to be rated "too little" on big picture perspective, growth orientation, and risk-taking.

Conclusion

The authors argue that women have become "boxed in" by excelling at technical mastery and results orientation, resulting in their being typecast in "hands on" rather than strategic roles. 

"[Women] ...get stuck in the technical expert, implementer role and are seen as not strategic enough to lead the enterprise. Further, they are so reliable in this role that they are often considered too valuable to put in other roles, roles that could broaden their perspective, expose them to working across boundaries, and connect their focus on execution to a bigger picture. There is a silent conspiracy among men and women themselves- everyone is complicit."