Democracy indices

Democracy indices are quantitative and comparative assessments of the state of democracy for different countries according to various definitions of democracy.

The democracies indices differ in whether they are categorical, such as classifying countries into democracies, hybrid regimes, and autocracies, or continuous values. The qualitative nature of democracy indices enables data analytical approaches for studying causal mechanisms of regime transformation processes.

Democracy indices differ in scope and weighting of different aspects of democracy, including the breadth of core democratic institutions, competitiveness and inclusiveness of polyarchy, freedom of expression, various aspects of governance, democratic norm transgressions, co-option of opposition, electoral system manipulation, electoral fraud, and popular support of anti-democratic alternatives.

Operating

 * The Economist Democracy Index, by the UK-based Economist Intelligence Unit, is an assessment of countries' democracy. Countries are rated as full democracies, flawed democracies, hybrid regimes, or authoritarian regimes. The index is based on five different categories measuring pluralism, civil liberties, and political culture.
 * V-Dem Democracy indices by V-Dem Institute distinguishes between five high-level principles of democracy: electoral, liberal, participatory, deliberative, and egalitarian, and quantifies these principles. The V-Dem Democracy indices include the Citizen-initiated component of direct popular vote index, which indicates the strength of direct democracy and the presidentialism index, which indicates higher concentration of political power in the hands of one individual.
 * Bertelsmann Transformation Index by the Bertelsmann Stiftung evaluates the development status and governance of political and economic transformation processes on the path to constitutional democracy and a market economy for developing and transition countries around the world. Bertelsmann Transformation Index categorizes countries into: hard-line autocracy, moderate autocracy, very defective democracy, defective democracy, consolidating democracy.
 * The Global State of Democracy Indices by International Institute for Democracy and Electoral Assistance assesses democratic performance using different types of sources: expert surveys, standards-based coding by research groups and analysts, observational data and composite measures.
 * The Democracy Perception Index, published annually by the Alliance of Democracies, is the world's largest annual survey on how people perceive the state of democracy (cf. the Corruption Perceptions Index which similarly seeks to measure public perception).

Indices measuring aspects of democracy

 * Freedom in the World, is a yearly survey and report by the U.S.-based non-governmental organization Freedom House that measures the degree of civil liberties and political rights in every nation and significant related and disputed territories around the world.
 * Effective number of parties is an index of the adjusted number of political parties in a country's party system.
 * Electoral Integrity Project surveys academics on the perceived electoral integrity of countries and subnational entities
 * Fragile States Index, formerly the Failed States Index, is an annual report that aims to assess states' vulnerability to conflict or collapse, ranking all sovereign states with membership in the United Nations where there is enough data available for analysis.
 * Gallagher index measures an electoral system's relative disproportionality between votes received and seats in a legislature.
 * The Pedersen index is a measure of political volatility in party systems.

Other measured aspects of democracy include voter turnout, efficiency gap, wasted vote, and political efficacy.

Historical

 * Democracy-Dictatorship Index is a binary measure of democracy and dictatorship.
 * Democracy Ranking is a democracy ranking by the Association for Development and Advancement of the Democracy Award.
 * Polity data series contains annual information on regime authority characteristics and covers the years 1800–2018 based on competitiveness, openness, and level of participation, sponsored by the Political Instability Task Force (PITF).
 * Boix-Miller-Rosato dichotomous coding of democracy, easy-to-observe characteristics, few evaluations by own researchers based on academic literature. As a classification: non-democracy to democracy.
 * Lexical Index of Electoral Democracy (LIED) by Skaaning et al. democracy's characteristics assessed with easy-to-observe characteristics, few evaluations by own researchers based on academic research. Then evaluating whether necessary characteristics are present or not.
 * The Index of Democratization created by Tatu Vanhanen

Difficulties in measuring democracy
Because democracy is an overarching concept that includes the functioning of diverse institutions which are not easy to measure, limitations exist in quantifying and econometrically measuring the potential effects of democracy or its relationship with other phenomena—whether inequality, poverty, education etc. Given the constraints in acquiring reliable data with within-country variations on aspects of democracy, academics have largely studied cross-country variations, yet variations in democratic institutions can be large within countries. Another way of conceiving the difficulties in measuring democracy is through the debate between minimalist versus maximalist definitions of democracy. A minimalist conception of democracy defines democracy by primarily considering the essence of democracy; such as electoral procedures. A maximalist definition of democracy can include outcomes, such as economic or administrative efficiency, into measures of democracy. Some aspects of democracy, such as responsiveness or accountability, are generally not included in democracy indices due to the difficulty measuring these aspects. Other aspects, such as judicial independence or quality of the electoral system, are included in some democracy indices but not in others.

Some measures of democracy, notably Freedom House and Polity IV, deploy a maximalist understanding of democracy by analyzing indicators that go beyond electoral procedure. These measures attempt to gauge contestation and inclusion; two features Robert Dahl argued are essential in democracies that successfully promote accountable governments. The democratic rating given by these mainstream measures can vary greatly depending on the indicators and evidence they deploy. The definition of democracy utilized by these measures is important because of the discouraging and alienating power such ratings can have, particularly when determined by indicators which are biased toward Western democracies.

Dieter Fuchs and Edeltraud Roller suggest that, in order to truly measure the quality of democracy, objective measurements need to be complemented by "subjective measurements based on the perspective of citizens". Similarly, Quinton Mayne and Brigitte Geißel also defend that the quality of democracy does not depend exclusively on the performance of institutions, but also on the citizens' own dispositions and commitment.

Critiques of measures of democracy
Data on democracy, and particularly global indices of democracy, have been scrutinized and criticized by various scholars. Gerardo L. Munck and Jay Verkuilen questioned various aspects of the data produced by Freedom House and Polity, such as the concept of democracy they measured, the design of indicators, and the aggregation rule. Political scientists Andrew T. Little and Anne Meng "highlight measurement concerns regarding time-varying bias in expert-coded data" such as Freedom House and V-Dem and encourage improving expert-coding practices. Knutsen et al. did not see evidence for time-varying bias in their expert-coded data and note the application of item response theory, factor analysis and estimates of uncertainties to limit expert biases while discussing concerns in operationalization of observer-invariant measures of democracy.