Every day, almost everything we do is about prioritisation. When I pick BLT or egg-mayo, I’m prioritising. When a small business owner decides whether to hire a new worker or install a new machine, they’re prioritising. When we decide to increase the cost of energy in order to reduce future climate change, we’re prioritising.

In fact, one of the most dramatic conflicts of the twentieth century was over how best to prioritise. Capitalists advocated a spread-out strategy, where individual choices combine to guide the priorities of entire societies. Socialists believed that a central organisation is needed to set priorities for societies.

Given how important prioritisation is, and how much people seem to care about doing it right, it’s startling that relatively little research is done into how best to prioritise the most important issues facing society. People do research on, say, the best ways to distribute humanitarian aid. But it wasn’t until 2004 that anyone thought to compare the best opportunities in humanitarian aid with the best opportunities in climate change adaptation technology or in reducing international trade barriers.

There are powerful reasons for avoiding the problem.

It’s hard to know where to start. We’d have to, for example, find some way to compare reductions in human rights abuses with reductions in child deaths. It seems unlikely we’ll ever find a rigorous way to do that.

It’s steeped in value judgements. No matter which way you go, you’ll have to make some ideologically loaded decisions. How much do you value unborn children? Animals? Artistic expression? Happiness? Some people will disagree with you no matter which attitude you take.

It is hugely complex to analyse. How much good can you do by delivering humanitarian aid to conflict zones? Well, are you going to take into account the risk that delivering aid will prolong the conflict? You really have to. But then perhaps a long conflict might be just the thing to force a whole region to take international cooperation and governance issues seriously. You can’t follow the causal chain all the way down the rabbit hole.

But none of those are good reasons. The simple truth is that we have no choice: we have to prioritise our work. Whenever any person, group or government makes any decision about how to spend or what to work on they are implicitly making these comparisons.

And they’re doing it badly, carelessly, and unconsciously.

There are some groups working to tackle the challenge of global prioritisation. Organisations like the Disease Control Priorities Project try to engage with a specific part of the challenge. The Copenhagen Consensus has engaged lots of specialists in a broad range of fields to present the case for many types of opportunity, and has worked on comparing the best of them.

No one, though, is addressing the problem that matters most to the members of 80,000 Hours. No one, that is, until now. Over the next few months, 80,000 Hours will be putting together a rough first pass at answering the question

“Suppose I’m willing to put the next ten years of my work behind any cause there is. Which one will make the biggest difference?”

It’s not going to be perfect, or even close. It will take advantage of modern research, with all the disadvantages and question-marks that entails. It will depend on a lot of assumptions, but where possible we’ll make those assumptions clear to let you decide.

The first step, and one of the most important, is the list of challenges. Here’s where you come in. I’ve got a list I’ll post in a bit, but I don’t want to bias you. What do you think the most important challenges facing humanity are? Post suggestions below.