Often we speak of 'children' with no one child in mind. Statistics reduce them to no more than data to be used in policymaking, academic discussion or press statements.
But, of course, every child has a unique experience, and while 'big data' is important for understanding trends and patterns, we mustn't forget the need to take the time to understand children's lives in more depth.
In its mission to help the most vulnerable girls across the world, Plan International UK has done just that. In 2006 we began a unique research study following a group of 142 girls from nine countries across three continents. All of these girls were born into poverty, but each of their life experiences was to be unique. The aim of the study was to track this cohort of girls from birth to 18 in order to have a better understanding of the reality of their daily lives.
After a decade of annual interviews with the girls and their families our researchers have collected a wealth of information. To this end, Real Choices, Real Lives provides a real insight into the way family and community shape girls' expectations of what they can do, and be, right from the very beginning.
Almost 80 years of working to support vulnerable children worldwide has taught us that too often, girls bear the brunt of poverty. Girls are subject to discriminatory attitudes which might mean, for example, that when parents can only afford school fees for one child, it's the son who goes. Or when a girl turns 12 or 13, she's seen as a child no longer, and becomes a wife. And when we set out ten years ago, we wanted to understand why.
What we've found, sadly, is that from a young age, girls are taking on these stereotypes in their behaviour, as well as their attitudes.
For example, of the 142 girls, all are responsible for completing daily household and domestic chores. A far cry from simply washing the dishes and tidying their rooms, some of these girls spend up to five hours a day caring for siblings or relatives, cooking, cleaning and fetching fuel or water. Born in 2006, the majority of these girls have only just reached the age of ten.
The division of labour is entrenched in family attitudes: the girls' brothers are rarely burdened in the same way. As nine-year-old Evelyn from El Salvador told us "It's not fair, because I do more than my brother. I told my mother but she did not say anything about it".
Nearly nine in ten of the girls' families reported that women and girls do most of the work at home; ten families share equally and in only three are men and boys taking on more of the domestic chores.
This expectation that girls will take on the bulk of domestic chores limits their horizons. It will cause them to drop out of school, and it will shape their own expectations of what they can do, and be, in adulthood.
But in spite of this, we also learn through our study that young girls are optimistic about their futures. Many of the girls that we interviewed are setting the bar high - aspiring to be doctors, nurses, and teachers. Of course, all of these professions require high levels of education.
And compared to their mothers, these girls are trailblazers, with all but one enrolled in primary school. This is a source of pride for many families involved in our study, with many parents having limited or no formal education at all.
But in the face of financial instability, it is not always guaranteed that families will continue to afford to send their daughters to school.
As the girls turn 10, they reach a pivotal stage in their lives. Entering adolescence, they will face more barriers - many will drop out of school, some will be forced into early marriage or be at risk of sexual exploitation.
At such an age where limitations are set and fates are decided, there is a window of opportunity to work with these young women to help them to fulfil their potential.
Plan International UK works with girls and their communities to eliminate all the barriers that stand in the way of equality - such as child marriage, violence in and around schools, poor sexual and reproductive health and rights, and economic insecurity.
Today, on International Day of the Girl, let's all take pause to recognise the depth of the challenges girls can face, and ask ourselves what we can do to support them.
To #StandUpForGirls on International Day of the Girl, visit www.plan-uk.org/standupforgirls
Read the executive summary of 'Real Choices, Real Lives: Ten Years On' here.