It has become a fashionable consensus that in the empowerment of adolescent girls and women lies the great panacea of development.
While Lady Thatcher famously argued that "nothing is more obstinate than a fashionable consensus", it could be argued that in this case, nothing is more right. But although I'll yield to no one in my belief in the power and potential of girls and young women, it is sometimes helpful – when such consensus exists – to consider, or reconsider, why we all feel so strongly.
Empowering adolescent girls with education is seen, rightly, as a prerequisite to development and growth. Put a girl through school and she is less likely to marry early and have children before she is ready. Economically, that means healthier, more productive families and greater earnings potential.
So there are proven economic benefits of investing in services targeted at adolescent girls. Some would argue that the effectiveness and output of tomorrow's labour force will be shaped by the investment made in today's adolescent girls.
This has long been labelled smart economics – and in recent years it has become the issue of choice for major corporate social responsibility programmes and celebrity endorsements. Don't doubt it – the added profile is welcome. Girls' education has never received greater attention, but with added profile comes a risk of homogenised arguments and disconnection with the real reasons behind the campaign.
While the economic arguments for investing in girls are compelling, this is a narrow articulation of empowerment that fails to recognise wider concerns around transforming unequal power relations between the sexes. By all means look at gender inequality through the prism of economics, but let's not forget this is a question, first and foremost, of rights.
In many parts of the world, traditional relations between the sexes systematically disadvantage girls throughout their lives, placing a lower value on them, thereby denying and violating their rights. At Plan we see this every day, from the girl sold off to early marriage in Bangladesh to the survivor of female genital mutilation in Mali to the girl kept from school under threat of violence in Pakistan.
We work to end these practices, and our most powerful means of doing so involves building girls' and women's confidence and capacity to ensure they are able to enjoy their rights as full and equal members of society.
This is a tested, uncontroversial approach. But the way we frame these issues is important – for Plan, the realisation of girls' rights must be pursued and strengthened as a goal in and of itself. This is about substantive, structural change, not just a means to an economic end.
No one would dare tell Malala that her education was simply a channel to Pakistan's economic betterment. Educating the 33 million illiterate women in Pakistan would no doubt pay dividends for that country's economy in years to come. But that is not the only reason why we should do it.
Our rights are inalienable, universal and permanent. Economic models, on the other hand, are shifting, nuanced and subject to interpretation. And so justifying investment in girls and women with economic arguments alone carries a risk: if the economic rationale for empowering girls is trumped by a more effective means to growth, what happens to girls?
It is through championing a rights argument that we can make a holistic, sustained and effective effort for girls and women. And because the rights argument applies to boys and men too, we minimise the notion of an "other" that an economically driven case might perpetuate. Girls' rights and boys' rights are inseparable; in fighting for one, we are fighting for both.
The importance of economic factors in female empowerment must not be understated. A young woman's ability to earn independently is an indisputable route to her better health and more fulfilling existence. But dismantling economic inequality is inextricably linked to dismantling political and societal inequality too. As well as supporting them into employment, we should support women and girls to participate in politics, undertake collective action, access leadership opportunities and enjoy the freedom to challenge and change social norms.
Underpinning all of this is that deceptively simple word: rights. And rights are the driver behind what Plan does, not merely the vehicle by which it does it. They are the means and the ends.
So yes, let's fight for girls' education, for better access to sexual health services and for lives lived without fear of violence and abuse – but let's not do it just because it's the smart thing to do, but because it is the right thing to do.
Tanya Barron is chief executive of Plan UK, which works with some of the world's poorest children. This blog is adapted from a keynote address at the Marshall Society's inaugural conference, delivered at Cambridge University on Saturday