New answers tagged conventions
It shouldn't focus on any item. The reason behind it, you wouldn't know which item he/she is going to tick next. Since to-do lists are not always ticked in consecutive order. Let the user choose which item to focus next himself/herself. Because auto focusing on the next or previous task might also lead to accidental ticks..
There's no research that I can see from my own quick Googling. The above answers are quite subjective also. If we are talking subjectively, I agree with @BDD - jumping to the next item is preferable considering it's user ordered. But let's be objective. I would recommend: Look at your competitors. I've screen shotted "Reminders" from iOS for you. They ...
With a list from top to bottom, I prefer "next one". Because when you're working with task 2, in most case, you already done with task 1. Should you comeback to task 1 then do one more step to work with task 3? People always look ahead, when need to look behind, we turn our head back.
I think either would be acceptable, but I would conduct user testing to see what your users think. In general though while I'm developing lists, I like to it jump to the next task, so it would go with this example and have all the tasks shift upward. So it would be something like this example. Task 1 item 2 is deleted Task 1 Task 2 ** ...
Top 50 recent answers are included