Earlier this month, I took part in a debate about whether Christmas had become a force for evil. I argued that the spirit of charity outweighed any benefits to corporations my gift-giving might have. We won. But I’m not sure I really believed myself.

Charitable donations over 2011-2012 declined by 20 per cent in real terms. Preach about charity, and you’re more likely to look holier than thou, rather than a conscientious citizen concerned with the common good. Some people might blame selfishness for this – anyone who does their college’s telephone campaign can testify that people say they “can’t afford it,” regardless of their actual income. But I think it’s more complex than that.

I have many reservations about modern charity. It is often used to do jobs I feel the government should be doing. Humanitarian Aid and a decent welfare system seem like more sensible solutions to hunger than relying on goodwill. Charity treats the symptoms rather than the cause. We rely on charity so much that now people refer to it as the voluntary or third sector. I visited an organisation called Mindroom, who provide support for people with learning difficulties. They need an iron determination in the face of poor public provision. Others may argue that we need the voluntary sector for its dedicated workforce. They do great work. But I wish the government would do it instead.

Another problem with charity is the overheads. Nearly a quarter of Oxfam’s donations are spent on marketing or administration. Charity is becoming an industry. Numerous charities compete against each other, and that brings pointed questions. The money might not be used as you would expect. A meaningful difference might not be made. You might give out more than you can afford. Doubt, not selfishness, is the major obstacle to people’s charitable intentions. And our doubt has made us cynical.

Philosopher Toby Ord, however, has tried to answer that doubt, creating Giving What We Can. This is an organisation with a very utilitarian approach called “effective altruism”. They compile existing research to assess how good a charity is, using something called DALYs (Disability-Adjusted Life Years) to quantify how many lives will be saved by extra donations. Donors can have confidence that their money is doing the maximum good possible. The phenomenon is now global, and (perhaps unsurprisingly) it has been endorsed by utilitarian philosopher Peter Singer.

GWWC’s unique selling point is “The Pledge”, whereby members allocate 10 per cent of their income to be given to the most effective charities, for the rest of their lives. For students, a pledge of one per cent of our spending money (excluding accommodation or tuition fees) is recommended. It is interesting to note the similarity of the 10 per cent pledge to the practice of Zakat in the Muslim world, as well as the Jewish practice of Tzedakah. Analysts estimate annual Zakat to be 15 times the total raised in global humanitarian aid, a whopping $200 billion. If these figures are to be believed, the modern citizen should not be asking how much they should give, but how best they should give it. As religion worked out long ago, the value of contributions is not as important as that lifetime commitment.

But can we afford it? This depends entirely on how comfortably you want to live. At the extreme end, Toby Ord gives away most of his salary, living on £18,000 with a wife and mortgage. That’s great, but it’s clearly not for everyone, and it’s probably not for me. But it makes keeping that 10 per cent of our salaries to ourselves look that bit more unnecessary; the average starting salary of a Cambridge Graduate is £25,797. After five years it will be closer to £40,000. Many Cambridge students are predestined to live on some of the highest salaries in the country. For them, 10 per cent won’t break the bank.

So I took the 10 per cent pledge myself. One question still tempers my enthusiasm. If everyone gives effectively, lesser known or local charities may be forgotten about. I’ve even heard “effective altruism” being called less altruistic. I’m not sure it matters, but my pledge for 10 per cent is only self-enforced, and so there is flexibility if I find a cause I care about. If, like me, you have doubted charity, The Pledge may have the answers to those doubts.