Available for all Magpi users with the Magpi+ ("Magpi Plus") app for Android and iOS.
The idea behind ranking is simple: when designing a form you enter a list of options. Then, when filling out the form on mobile, you drag and drop the options into the desired order:
In question 11 in the screenshot shown above (click to enlarge the image), there are three options. After dragging into order, Magpi will store a number from 1 to 3 for each of the options, with the most highly ranked one being assigned a "3" (n, the number of options) and the least important being assigned a "1".
The dataset for this question will look like this: