Comparative Political Data Sets

Research project

The Comparative Political Data Sets (CPDS for short) are three separate datasets compiled by researchers at the University of Berne. The three datasets contain a collection of political and institutional data, but cover different countries and time periods. The dataset called CPDS I (Armingeon et al. 2011) covers the OECD countries for the period 1960-2009 and was assembled as part of the research projects Die Handlungsspielräume des Nationalstaates and Critical Junctures: An International Comparison. The second dataset, CPDS II (Armingeon and Careja 2008), covers 28 post-communist countries for the 1989-2008 period, and was compiled as part of the research project Forms of Government: A Comparative Data Set for 28 Eastern Countries. The third dataset, CPDS III (Armingeon et al. 2011), covers 35 OECD and/or EU member countries for the 1990-2006 period. The data in this dataset are mainly drawn from the other two, but it differs from them in some respects.


  1. Comparative Political Data Set I
  2. Comparative Political Data Set II
  3. Comparative Political Data Set III

Comparative Political Data Set I


Comparative Political Data Sets






23 countries

Last reviewed


Data types and sources

Political variables based on expert coding and election data. Socio-economic data based on official registers, national accounts and surveys, compiled from international statistical organisations.

Data download

Comparative Political Data Set I


The core of the dataset is composed of variables related to the political system and electoral rules. In addition, the dataset contains some socio-economic variables. The dataset covers many of the same topics as CPDS II, and a number of the variables are identical. However, in some cases variables measuring the same concept are operationalised differently in the two datasets, and some variables are included only in one of them.
The CPDS I contains approximately 100 variables organised in thematic groups:

  1. Governments. Variables describing the party composition of government, changes in government and type of government (minority/majority, coalition/single party).
  2. Elections. Date of election, voter turnout, various parties’ share of votes and various parties’ share of seats.
  3. Women in parliament. Percentage of women in parliament.
  4. Party system. Various indices measuring the degree of disproportionality in the electoral system and the effective number of parties (Rae, Laakso-Taagepera, Gallagher indices).
  5. Institutions. Some of the variables are various indices taken from Lijphart (1999), measuring aspects of the electoral system, e.g. federalism, party system, executive-legislative relations and degree of judicial review. The remaining variables are based on other sources – many are taken from Huber et al. (2004) – and measure various institutional features, such as institutional constraints on central state government, degree of integrated economy, federalism, presidential/parliamentary system and use of referenda.
  6. Central bank independence. Various indices measuring different aspects of central bank independence.
  7. Openness of the economy. Index for financial openness, index of restrictions on payments and receipts of goods, and index of restrictions on payments and receipts of capital.
  8. Macroeconomic data. Variables such as GDP growth, government debt, annual deficit, and imports and exports.
  9. Labour force data. Total and civilian employment and unemployment, employment in various sectors, participation rate, standardised unemployment rate.
  10. Trade unions and industrial disputes. Variables measuring various aspects of labour disputes (strikes and lockouts) and number of union members.
  11. Public social expenditure and revenue data. Variables such as social security transfers, public social expenditure and expenditure on health.
  12. Family policy. Various public and mandatory cash benefits as percentage of GDP.
  13. Labour market policy. Variables primarily measuring government expenditure on labour market policies.
  14. International Labour Organisation. Number of ILO conventions ratified.
  15. Demographic data. Population size, total and by age.

Geographical coverage

The dataset covers 23 OECD countries.

Time coverage and updates

The dataset provides annual data from 1960 to 2009. Some years are missing for a few countries, notably Mediterranean countries during the period they were ruled by non-democratic regimes. The dataset will normally be updated annually. Last update: 28 September, 2011.


Generally speaking, the dataset is described in a fair amount of detail in the codebook, which is available for download from the website. However, the coding rules for variables reproduced from other sources are not specified in sufficient detail. Frequently the codebook does not specify how these variables are coded; it merely refers to the original source. This makes it unnecessarily time-consuming for users to find out how the variables are coded and what they measure. Furthermore, sometimes the original source does not provide any clear coding rules either. Many of the institutional variables are taken from the Comparative Welfare States Dataset (Huber et al. 2004), but this source says practically nothing about how variables such as federalism, presidentialism and electoral system are coded.

Access conditions and cost

Available free of charge.

Access procedures

Predefined table.

Data formats


Comparability and data quality

The data quality appears to be generally good, though there are some instances of inaccurate data or debatable coding practices. See Chapter 5 in Rydland et al. (2008) for a general discussion of data on political institutions.


Armingeon, Klaus, and Romana Careja. 2008. Comparative Data Set for 28 Post-Communist Countries, 1989-2006. Institute of Political Science, University of Berne.

Armingeon, Klaus, Romana Careja, Panajotis Potolidis, Marlène Gerber and Philipp Leimgruber. 2011. Comparative Political Data Set III 1990-2009. Institute of Political Science, University of Berne.

Armingeon, Klaus, Marlène Gerber, Philipp Leimgruber and Michelle Beyeler. 2011. Comparative Political Data Set 1960-2009. Institute of Political Science, University of Berne.

Huber, Evelyne, Charles Ragin, John D. Stephens, David Brady and Jason Beckfield. 2004. Comparative Welfare States Data Set, Northwestern University, University of North Carolina, Duke University and Indiana University.

Lijphart, Arend. 1999. Patterns of Democracy: Government Forms and Performance in Thirty-Six Countries. New Haven and London: Yale University Press.

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).