80000 hours use three factors to measure the effectiveness of working on different cause areas: Scale, neglectness and solvabilty. But maybe urgency is important, too. Some areas can be waited for a longer time for humans to work on, name it, animal welfare, transhumanism. We can work on this 500 years later (if we're alive) But some problems have urgency, like: AI safety and biorisk. Should we work more on areas that are more urgent for us to solve?
Ok so I'm trying to come up with an example where
I think an example that perfectly reflects this is hard to come up with, but there are many things that are close.
Of course, these vacuums are still underspecified. Opportunity cost is rarely just about trading off 2 objects -- in the real world we have many options. I think you are thinking more about cause areas and I'm thinking more about specific interventions. However, I think this could extend more broadly but it would be more confusing to work out.