Girls grow up in this culture believing their value to be tied to their appearance and sexuality and suffer greatly if they don’t conform to these expectations; studies have shown that by age 12, girls’ self-confidence will plummet and not recover for nine years — which is in sharp contrast to boys of the same cohort.

"Do you really think a woman could be elected president?" "Critics take aim at US women soccer team's style." "Dalai Lama says a female successor must be attractive."

A quick scan of headlines leaves little doubt: despite all the progress women have made in the workplace, home and in cultural representations, there remains a significant and troubling inequality in the way society looks at, talks about and values women and girls.

Over and over and over again, women and girls are taught they are inherently less valuable than men, and their primary value lies in their appearance, desirability or proximity to men. The consequences can be devastating - ranging from unequal pay and disparities in medical care, to enabling environments that permit sexual harassment and assault. Other documented outcomes that have been linked with poor self-esteem include increased incidences of eating disorders, obesity, smoking, early onset of sexual activity and alcohol abuse.

In a culture that has long considered women a commodity, it is unsurprising girls grow up believing their value is tied to their appearance and suffer greatly if they don't conform to particular expectations. Studies have shown by age 12, girls' self-confidence will plummet and not recover for at least nine years, which is in sharp contrast to boys of the same cohort.

The explosive growth of social media, particularly visual formats like Instagram and Snapchat, further deeply ties girls' sense of self-worth to their appearance and others' reactions to it by inviting comparisons to curated, filtered images, often perfected with "beautifying" apps designed expressly for this purpose. A recent report discussed the alarming nationwide increase in teen girl suicides: since 2007, the suicide rate for girls age 10 to 14 rose by nearly 13 percent, nearly double the rate for boys, and suggested self-esteem issues, bullying and social media use are driving the rise.

We know there are meaningful linkages between appearance, self-esteem, and achievement. The challenge for girls globally is to break the link between appearance and outcomes, while reinforcing the importance of healthy living, equal access to opportunity, and support for perseverance, courage, leadership, passion, and self-determination.

In October of 2013, while working for then New York City Mayor Michael Bloomberg, Samantha Levine created and oversaw the launch of the "I'm a Girl" campaign, a first in the nation girls body image and self-esteem initiative, to address these very issues. Designed to help girls believe their value comes from their character, skills, relationships and attributes - not appearance - while also expanding the definition of beautiful beyond an unhealthy, unrealistic ideal, "I'm a Girl" included a $250,000 public education campaign, supportive school curriculum as well as sports and volunteer components. The public reaction was instantaneous and positive, with hundreds of people writing in from around the world asking for posters and how to bring it to their community. Unfortunately, the Mayor's term ended three months after the campaign launched and we did not have the opportunity to build on the success.

A Different Measure will bring the effort back to life, building on the vision of "I'm a Girl" and expanding it into a national movement, supported with ongoing public awareness, parent-child engagement and communications advocacy. To really drive systemic change, we need an ongoing, focused and sustained effort to change the way we value girls.

It's time to start using a Different Measure.