Liberal democracy index during each prime minister's tenure

Every prime minister since 1991, ranked by how the liberal democracy index changed from their first day in office. Politare shows what happened during a tenure; it does not claim the office-holder caused it.

#	Prime minister	In office	Total	Per year	Chart
1	Jim Bolger	2 Nov 1990 – 8 Dec 1997 from 1991	+1.6 points 1991 → 1997	+0.3 points/yr
2	John Key	19 Nov 2008 – 12 Dec 2016	+0.3 points 2008 → 2016	0.0 points/yr
3	Helen Clark	10 Dec 1999 – 19 Nov 2008	0.0 points 1999 → 2008	0.0 points/yr
4	Jacinda Ardern	26 Oct 2017 – 25 Jan 2023	0.0 points 2017 → 2022	0.0 points/yr

Sorted by total, highest first. Every row is indexed to the last count complete before the first day in office ("from" marks a start that had to move because that count had no data, or because the period cut it); Levels are per cent changes, rates are differences in points; "per year" compounds levels and divides rates. Tenures with under 12 months, or under three observations, are left out. points, 0 to 100, V-Dem's 0 to 1 index times 100 · V-Dem Institute, V-Dem dataset v16 (v2x_libdem): the liberal democracy index, electoral democracy plus the checks on the executive and the rights of the person, as V-Dem's country experts rate them, with V-Dem's confidence interval; the 0 to 1 index times 100 · New Zealand data · as of Jul 2026.