It is indicated in the CVA technical paper that the recommended number of tasks is 3 x (total # levels - # attributes + 1).
Just to make sure I understand this right, say we have 3 attributes with 3 levels each. This means that there are 27 total possible combinations. If I go by the formula above, I get: 3 x (9 - 3 + 1) = 24 tasks, which is almost all the possible combinations. If we have 3 attributes, with respectively 2, 2, 3 levels, there would be a possible 12 combinations, but the formula would give us: 3 x (7 - 3 + 1) = 15 tasks.
Am I misinterpreting the formula?