Rank Voting is useful when you have a large number of items to rank
or order using a large number of people indicating their preference.
Rank Voting is an option on a competition that considers each voters
ordered preference for images.
When voting on images using Rank Voting, you order thumbnail images
by setting a numeric "rank" value on your favorite images.
The lowest number is considered your first place selection.
Remaining preferences continue in numeric order.
Initially, you can assign any numeric values to any number of images.
Duplicate numbers and gaps are allowed. When you save you current set of rankings,
the thumbnails will appear at the start of the list. Other images will retain
their relative position as you last set them, perhaps with a drag and drop.
When you have finished ranking images in each of the Competition Levels
for a Competition, you check a box to commit your votes. This will renumber
your rank values to start sequentially from one.
Rank values in excess of the maximum votes allowed will be set to zero.
Competitions are should limit the maximum number of "votes" (rankings) each person may
cast. This means that only the first few images will be considered when computing
a composite "Voting Rank". The limit is displayed on the page where you cast votes.
You cannot vote for your own images, so those images are always placed
at the end of the list while you are voting.
When voting for Image Sequences, you vote by setting a rank value on the first image in the
sequence. The display will update with the remaining images following that image.
Voting Rank Computation
A composite "Voting Rank" is computed from all of the votes cast.
This calculation takes place when the voting period expires.
The method used is similar to "Ranked-Choice Voting" or "Instant-runoff voting",
but that system does not work well when you want an ordered list of preferences.
To account for the wide variety of votes that may be cast for an image,
a point system is used to normalize the effect of different place preferences
for an image.
Each vote is assigned points equal to the Maximum Number of Votes
per User minus the rank value plus 1. Images with no rank votes get zero points.
For example, if 4 votes were possible, a vote of 1 would get 4 points,
a vote of 2 would get 3 points, 3 gets 2, and 4 gets 1.
Rankings can then be assigned to each image based on its points, ranging from 1 to
the Maximum Votes Per User. Ties are possible, but minimized by the voting process.
The Voting Rank computed for each image is stored in the competition entry
and can be used for assigning awards.
A detailed example of the Rank Voting calculation
can be downloaded