Polyarchy Dataset (Vanhanen)

Research project

An earlier version of what is now called the Polyarchy Dataset was produced by Tatu Vanhanen in the early 1970s. The dataset contains an index of democracy, which has been used by Vanhanen in several studies that seek to provide a theoretical explanation for the emergence of democratic regimes (e.g., Vanhanen 1984, 1997, 2003).

The index is usually named the Vanhanen index after its author, but was given the name Polyarchy when the dataset was first made public in electronic form (Wilhelmsen 2006: 35). The dataset is maintained by the International Peace Research Institute (PRIO) in Oslo, Norway.


Polyarchy Dataset

Polyarchy Dataset


Polyarchy Dataset (Vanhanen)


Excel, ASCII, Stata, SPSS




187 countries

Last reviewed


Data types and sources

Composite index based on election data.

Data download

Polyarchy Dataset


The dataset contains seven variables, including a democracy index. The index takes Dahl’s (1971) discussion of democracy (or polyarchy, hence the index’s name) as its point of departure, and attempts to measure democracy with two variables: competition and participation (Vanhanen 2000: 253). Both variables are calculated using election data, and the democracy index is estimated by combining the two.

Geographical coverage

The dataset covers 187 countries, including some historical political entities.

Time coverage and updates

Years covered: 1810-2000.Years covered in the official version. An unofficial version used in Wilhelmsen (2006) contains data for the period 1810-2002. Frequency of updates not stated.


The background for the dataset and the computation of the variables are described in detail in a manuscript by Vanhanen available for download online. A revised version of the manuscript has been published in Journal of Peace Research (Vanhanen 2000).

Access conditions and cost

Available free of charge.

Access procedures

Predefined table.

Data formats

Excel, ASCII, Stata and SPSS.

Comparability and data quality

All attempts to measure the degree of democracy quantitatively are contested, and Vanhanen’s index has been subject to much criticism. The conceptualisation of democracy has been criticised for relying on a far too narrow understanding of the concept, and the two variables used to measure participation and competition are by many scholars considered to be, at best, poor approximations of the underlying concepts. Other scholars have argued that a minimalist definition of the concept is advantageous since it avoids blurring the boundaries between regime type and other political phenomena, political entities or aspects of the state, and thus enables extensive empirical analysis of causal relationships (Cheibub and Gandhi 2004). The Polyarchy Dataset has the advantage of relying on "objective" and easily available data. However, the contrast between subjective and objective indicators should not be overstated, since the selection and operationalisation of the indicators are shaped by subjective judgements.

See Hadenius and Teorell (2005), Munck and Verkuilen (2002) and Chapter 5 in Rydland et al. (2008) for a detailed discussion of the comparability and quality of democracy indices in general.

Electronic resources

Polyarchy - Dataset Manuscript

Polyarchy - Dataset Old versions


Cheibub, José Antonio, and Jennifer Gandhi. 2004. “Classifying political regimes: a six-fold measure of democracies and dictatorships”. Prepared for the annual meeting of the American Political Science Association, Chicago, September 2004.

Dahl, Robert A. 1971. Polyarchy: Participation and Opposition. New Haven and London: Yale University Press.

Hadenius, Axel, and Jan Teorell. 2005. “Assessing alternative indices of democracy”. C&M Political Concepts Working Papers 6, IPSA (August).

Munck, Gerardo L., and Jay Verkuilen. 2002. “Conceptualizing and measuring democracy: evaluating alternative indices”. Comparative Political Studies 35 (February): 5-34.

Rydland, Lars Tore, Sveinung Arnesen and Åse Gilje Østensen. 2008. Contextual data for the European Social Survey. An Overview and assessment of extant resources. NSD Report No.124, Norwegian Social Science Data Services (NSD).

Vanhanen, Tatu. 1984. The Emergence of Democracy: A Comparative Study of 119 States, 1850-1979. Commentationes Scientiarum Socialium No. 24. Helsinki: Finnish Society of Sciences and Letters.

Vanhanen, Tatu. 1997. Prospects of Democracy: A Study of 172 Countries. London: Routledge.

Vanhanen, Tatu. 2000. “A new dataset for measuring democracy, 1810-1998”. Journal of Peace Research 37 (2): 251-265.

Vanhanen, Tatu. 2003. Democratization: A Comparative Analysis of 170 Countries. London: Routledge.

Wilhelmsen, Lars. 2006. A Democratic Peace Revisited: Measuring Democracy in International Relations. Master’s thesis. University of Oslo.