How democratic are the reformed electoral systems used in mayoral and devolved elections?

As part of the 2017 Audit of UK Democracy, Patrick Dunleavy and DA staff examine how democratic the two big reformed electoral systems used in the UK – the ‘Additional Members System (AMS)’ and the ‘Supplementary Vote (SV)’ are, and how successful they have been in showing the way for more modern electoral systems under British political conditions.