The most central issues are those that are connected to the largest number of other highly central issues. The algorithm we use to calculate this is very similar to Google's PageRank technique. Once we have the most central issues, we can strip out words like 'think' and 'because' and what remains are the words (and pairs of words) that best characterise the central themes of the debate.

See the central issues change as the programme unfolds. Use the and buttons to see updates at regular intervals.