As part of his PhD research, Zahir helped Gurgaon ki Avaaz run a singing talent hunt on community radio and IVR. During the first phase of the competition, listeners called the IVR to leave their song entries by singing into the phone. During the second phase, listeners called to vote on the songs. We experimented with two kinds of IVR voting interfaces — best of two, where a pair of songs were presented the callers had to tell us the better on. We then aggregated the pairwise comparisons to derive a global order. In the second variant, a series of songs were presented to the callers and they had to up/down vote each song.
It was a great experience and told us how to enable such formats on IVR. Read the full paper dev2013v10.