Data

OPAMED: the One-Party Membership Dataset

The One-Party Membership Dataset (OPAMED) is a comprehensive dataset on party membership in autocracies, covering 42 ruling parties across party-based regimes from 1945 to 2020, and primarily introduces: absolute party membership numbers, party size, and party membership volatility. Along with the national absolute numbers, the second variable measures the membership-to-population ratio, while the third measures the rate of co-optation growth from one year to the other.

You can merge it with other PartyFacts datasets and V-Dem data by using “year” and “country_id” variables.

Cite as:

Angiolillo, F. (2024). Introducing the One-Party Membership Dataset: A dataset on party membership in autocracies. Journal of Peace Research, 61(4), 694-708. https://doi.org/10.1177/00223433231155278

Variables Contribution

Party-System Indices

The party-system indices refer to a variety of latent positions that party systems have on several policy orientations and governance. The Party Systems indices are designed by aggregating individual parties’ policy orientations in a given country-election-year using data from the Varieties of Party Identity and Organization (V-Party, v2) during the period between 1970-2019 for 178 countries. To each index, we also provide the sub-index only focusing on the government and opposition parties. These indices are:

  1. Party-System Democracy Index (v2xpas_democracy)

  2. Party-System Religion Index (v2xpas_religion)

  3. Party-System Exclusion Index (v2xpas_exclusion)

  4. Party-System Left-Right Index (v2xpas_economic)

You can find details in the V-Dem Codebook (v14) pp. 323-329, and download the variables by downloading V-Dem dataset v14 or later versions (there is also an R package “vdemdata” that features these variables along all other V-Dem variables).

An easy way to merge Party-System Indices!

If you want to merge any of the party-system indices with data from QoG, UCDP, COMPLAB, REPDEM, V-Party, and ERT you can download a user-tailored dataset from Demscore

Cite as:

For the Party-System Democracy Index (PSDI):

Angiolillo, F., Wiebrecht, F., & Lindberg, S. I. (2023). Democratic-Autocratic Party Systems: A New Index. V-Dem Working Paper 143.

For all other Party-System Indices:

Angiolillo, F., & Wiebrecht, F. (2023). From Individual Parties to Party Systems: A New Approach to Calculate Party Systems’ Variables. V-Dem Working Paper, 146.