If you’re feeling sorry for yourself this budget day, as a member of the “squeezed middle”, some statistics might put your plight in context.

Ask yourself, what percentage of the world’s population is above you in income, and what percentage is below? William Mac Askill has put this question to residents of the US and UK and “they typically guess they fall into the 70th or 80th percentile” in terms of wealth.

In fact, he says, “If you earn above $52,000 (€46,450) a year, then, speaking globally, you are part of the 1 per cent. If you earn at least $28,000 (€25,000) – that’s the typical income for working individuals in the US – you’re in the richest 5 per cent of the world’s population. Even someone living below the US poverty line, earning just $11,000 (€9,800) a year, is still richer than 85 per cent of people in the world.”

Mac Askill, a leading figure in the "effective altruism" movement, hopes to remind us not just how fortunate we are in the western world – relatively speaking – but also, how we have a significant capacity to do good. In his book Doing Good Better, the Oxford-based philosopher puts paid to the lie that development aid does not work, pointing to improved educational and health indicators which can be traced to such funding. The eradication of smallpox alone is estimated to have saved between 60 million and 120 million lives in the past 40 years.

But when it comes to individual aid projects there are wildly differing results. As a rule of thumb, he says people should give money to charities that are transparent about their funding, have low overheads and high impact. An appealing aspect of his message is that you don’t have to join the aid corps to transform the lives of thousands of people, you merely have to rethink how to use your income.

Thus, he provides today's "Unthinkable" idea: "We have the opportunity to provide a benefit for others that is one hundred times greater than the benefit we could provide for ourselves."

What’s the best way of measuring effectiveness in charitable giving?

“Economists have spent decades conducting research on how to best measure health benefits. They have developed a metric called the quality-adjusted life year, or QALY, in order to help make decisions about how to prioritise among different health programmes...

“Even a rough idea of how many people are affected, and by how much, is often enough to show that one programme has a much larger impact than another.”

How do you respond to the argument that some of the best forms of altruism – like showing solidarity, volunteering or being present with people at times of need – can't be measured?

“In the sense in which effective altruists use the term, ‘altruism’ need not imply any sacrifice. What matters is how much we benefit others, not what costs we incur or what motivates we have. It follows that ‘the best forms of altruism’ are things like donating to a high-impact charity or pursuing a high-impact career.

"These things can be measured, and are in fact being measured by the effective altruist community. GiveWell, a charity evaluator, measures how much money they move; and 80,000 Hours, a career advising service, measures how many people have significantly changed their career plans.

“The impact of some activities, such as campaigning for political change, is harder to measure than others, such as distributing bed nets. But, if we think about impact in terms of how many people are benefitted or harmed, and by how much, then in principle at least the impact of all activities can be measured – it might just, in some cases, be very hard to do so.”

You have written about the phenomenon of "moral licensing", how people who perform one good act often compensate by doing fewer good acts in the future. How does one guard against this?

“My advice is twofold. First, make sure that when you do good, you do the most good you can. Some ways of using your time or money can have hundreds or thousands of times as much impact as others.

“So by using your resources intelligently, you can multiply your impact by a huge factor. As a result, even if you succumb to moral licensing, you still end up doing a lot of good.

"Second, pre-commit to help others. 'Giving what we can' allows you to pledge to give 10 per cent of your lifetime income to highly cost-effective charities. By signing their pledge, you guard against moral licensing, insofar as the temptation not to give later by virtue of having given now is counteracted by the public commitment to keep giving indefinitely."

Does “earning to give” really qualify as altruism if you make your money by dubious ethical means?

“Earning to give is the pursuit of a highly lucrative career with the goal of donating a significant portion of one’s earnings to charity. The case for ‘earning to give’ is quite strong. Using GiveWell’s estimates about the cost of saving a life and data about the salaries associated to various careers, one can conclude that a person earning to give could easily save hundreds of lives during their lifetime.

"We rightly revere those who, like Oskar Schindler, saved countless Jews during the Holocaust. But most of us have the power to do something equally admirable.

“Of course, this doesn’t mean that one should work in harmful industries. Effective altruists do not condone causing harm to others to promote the greater good. But this isn’t an argument against earning to give, since there are many lucrative careers that are also morally unproblematic, such as tech entrepreneurship.”