Original: Under the supplementary voting system employed for the election, only the votes cast for Livingstone and Norris were considered in the second round, where Livingstone won with 58% of first - and second-preference votes, versus 42% for Norris.
Simplified: Under the modified instant-runoff voting system employed for the election, only the votes cast for Livingstone and Norris were considered in the second round, where Livingstone won with 58% of first - and second-preference votes, versus 42% for Norris.