V-Dem Democracy Measurement

Electoral (free and fair elections and the institutions of representation), liberal (protection of individual rights, rule of law, and checks on power), participatory (active and broad citizen participation beyond elections), deliberative (decisions reached through reasoned public deliberation rather than coercion or emotion), and egalitarian (equal distribution of resources, power, and capabilities across social groups). Each has its own index built from disaggregated indicators.

Each indicator is coded by multiple experts, and a Bayesian item-response-theory measurement model aggregates their ratings while estimating each coder's reliability and systematic strictness or leniency, using anchoring vignettes and overlapping coders to calibrate across experts. The model outputs point estimates with credible intervals, so the remaining uncertainty is quantified rather than hidden — though expert judgment is still the underlying input.

It depends on the question. Polity gives a single, institution-based regime score with very long historical coverage and is simple to use. V-Dem offers many disaggregated, multidimensional indices with uncertainty estimates, ideal when you care about specific democratic components or gradual change. For long-run, parsimonious regime classification Polity is convenient; for detailed, component-level analysis or studying backsliding, V-Dem is generally preferred.