Two years ago, an alarming statistic in a World Health Organization (WHO) report brought to light a troubling and mostly unrecognized problem: Suicide is the leading cause of death for adolescent girls ages 15 to 19 globally.

The WHO report linked gender inequality and harmful norms to its disturbing finding. In communities around the world, girls struggle with discrimination, isolation, exploitation, and abuse. Millions of girls are forced to marry as children, drop out of school, and carry the burden of household chores. Too many girls endure violence; too many are denied basic health care, including mental health care.

It is encouraging that adolescent girls are finally on the global agenda and their needs and rights are accounted for in the Sustainable Development Goals.

Still, the reality is that for the world’s 15- to 19-year old girls, we simply know more about what they succumb to than how they actually live.

That is because our understanding is clouded by significant gender data gaps – from mental health, to economic opportunity, to violence, to girls’ needs in emergency settings – that interfere with our ability to count and account for girls. Meanwhile, the data we do have is often old, unreliable, or deeply biased. Data about girls ages 10-14 is particularly scant. The result is that we don’t have the clear picture we need to assess the lives of millions of adolescent girls.

Girls’ absence or neglect from global, regional, and national data reflects the larger reality that, all too often, girls of all ages are deprived of voice and dignity in their families and communities.

In a world where the maxim is “Measure what matters,” the message about and to girls is clear: “You do not matter. You have no value. Your life is not worth counting.” Seen in that light, the suicide rate of adolescent girls takes on new and tragic meaning. They are not just statistics, after all; behind each number is an adolescent girl who felt so hopeless, worthless, and alone that death seemed like her best option.

The reality is that for the world’s 15- to 19-year old girls, we simply know more about what they succumb to than how they actually live.

The exclusion and social isolation that so many girls face is inextricably intertwined with their human development challenges. Yet, by the same token, if we invest in collecting data on their lives, the world can send a powerful signal about the value we place on girls and the commitment we share to their futures.

That is why, to achieve real progress with and for adolescent girls, we have to stop simply talking about them and start talking with them.

We need to ignite what our colleagues at Data2X call a gender data revolution, collecting more and better data on the lives of girls, so we can better understand their experiences and be better prepared to meet their needs and support their rights and achievements.

By talking to – and, more importantly, listening to – girls and ensuring their experiences are captured in data, we can uncover hidden challenges, design investments that work for them, deliver the right solutions, and open an ongoing conversation about their lives and aspirations. Moreover, we can demonstrate the respect and recognition that signal – not only to girls themselves, but to everyone – that girls’ lives and experiences matter.

Through the UN Foundation’s Girl Up campaign, for example, we’ve observed that creating safe spaces for girls can be transformative, granting girls the confidence and comfort to speak about their lives, to ask questions about their rights, and to connect with other girls – building a sense of belonging that is empowering in its own right.

We believe that providing these opportunities is both a matter of justice and a matter of smart development – because change starts with a girl. When she is healthy, safe, educated, and empowered, she is one of the world’s most powerful forces for peace and progress.

Fortunately, the gender data movement that started long ago at UN agencies and national statistical offices has recently grown in prominence, gaining new partners, funders, and energy. From Data2X to UN Women’s “Making Every Woman and Girl Count” initiative to the Plan International-convened “SDG Tracker,” a range of civil society partners, governments such as Canada, and funders are coalescing around this issue and building momentum to improve our capacity to collect, analyze, and share data.

Advances in technology and data methodology, including the increasing availability of mobile phones, can also open new doors for more and better data, including the voices of girls if we do it right.

With the launch of the Sustainable Development Goals, there is renewed momentum around ensuring that girls’ voices are heard and their unique and particular needs met. We must seize this historic opportunity to put girls at the heart of our work.

Every girl deserves to be connected and counted. Every girl deserves to be heard. The gender data revolution helps give girls a voice. It is up to us to listen.

Kathy Calvin is President and CEO of the United Nations Foundation. Kim Samuel is President of The Samuel Family Foundation and Professor of Practice at the Institute for the Study of International Development (ISID) at McGill University.

Image: Young girls taking part in the International Day of the Girl event at the UN in 2014. UN Photo/Amanda Voisard.