The problem is how much to pay? And does paying help the candidate at all. Usually the candidate is taking some kind of leave, and is already being paid so they

The problem is how much to pay? And does paying help the candidate at all. Usually the candidate is taking some kind of leave, and is already being paid so they don't desperately need the money. I think better than paying is to have equal consideration. For example if a company gets 100 devs to do a 2hr online dev test, then picks 1 for an interview then they have generated 200 hrs of work in the community but only at a cost of 2 hr of their time. This is like 'spamming' in a sense. And this is what can waste a lot of time for candidates. They should have filters before those stages to minimise the time of candidates that they waste.