The ranking multipliers dialog allows you to specify your own ranking summary preferences. The ranking graph display has a summary option which shows a value dependent on what the responses are. It calculates the summary score by adding up the numbers of people who chose each option, and multiplying them according to whether it was the first preference, second preference, and so on.
So for an element with 5 people who chose it first, and 3 people who chose it second, and 4 people who chose it as their third preference, the standard values will give it a score of:
(5 x (1 / 1)) + (3 x (1/2)) + (4 x (1/3)) = 7.833
This dialog allows you to alter the calculation as you require. You can set it in advance of the activity, and also while the activity is displayed using the graph options menu.