This method involves identifying how much effort (time, cost etc) each task is likely to take and how much value (benefit) it is likely to deliver.
Using this approach you can identify the items that will get you 'biggest bang for buck' and the stuff that's just going to be a bit of a time suck for no real benefit. This can also help if you want to apply the Pareto Principle...
This rule states you should focus 20% of your time on activities that will provide 80% of results. It applies equally to tertiary studies as it does in the workplace.
If you have a list of 10 things to do, two of them will be far more valuable than the other eight items put together. Even if all 10 tasks take the same to complete, those two items or the 'vital few' will contribute to your goals far more than the 'trivial many'.
An example of this is trying to lose weight. You may come up with 10 things that will help you lose weight. But reducing calories and increasing daily exercise are going to be the two tasks that will get you 80% to success of your weight loss goal.