A 2011 McKinsey report noted that men are promoted based on potential, while women are promoted based on past accomplishments.14 In addition to the external barriers erected by society, women are hindered by barriers that exist within ourselves. We hold ourselves back in ways both big and small, by lacking self-confidence, by not raising our hands, and by pulling back when we should be leaning in. We internalize the negative messages we get throughout our lives--the messages that say it's wrong to be outspoken, aggressive, more powerful than men. We lower our own expectations of what we can achieve. We continue to do the majority of the housework and child care. We compromise our career goals to make room for partners and children who may not even exist yet. Compared to our male colleagues, fewer of us aspire to senior positions.