Terrorism in Western Europe: Events Data

Research project

The dataset Terrorism in Western Europe: Events Data, collected by Jan Oskar Engene (University of Bergen), records internal terrorist activities in western Europe after 1950. The dataset was collected for the purpose of analysing patterns of domestic terrorism in western Europe. Analyses of the dataset have been published in Engene (2004).


Terrorism in Western Europe: Events Data (TWEED)



Terrorism in Western Europe: Events Data






18 countries

Last reviewed


Data types and sources

Events data coded by Engene based on Keesing’s Record of World Events, a source that collects news reports on a daily basis from all over the world.

Data downloads

TWEED project website

Data from Journal of Peace Research


The dataset records terrorist-initiated events in western Europe after 1950. The dataset is limited to internal terrorism, that is, acts of terrorism initiated by people and groups from western Europe. For each event, the dataset contains information on the following: date of event; name of country where the event took place; name of acting group or organisation; number of people killed or injured; type of violent means employed; government reaction; regional origins; ideological profile; and agent’s attitude towards the state. The dataset consists of 52 variables.

Geographical coverage

The dataset covers 18 countries in western Europe.

Time coverage and updates

Years covered: 1950-2004. Frequency of updates not stated.


The dataset is described in Engene (2007). The coding rules are explained in a fair amount of detail in a downloadable codebook (Engene 2006).

Access conditions and cost

Available free of charge. The dataset can be used for educational and research purposes by students and researchers, provided that proper acknowledgement and references are given.

Access procedures

Predefined table.

Data formats


Comparability and data quality

Not examined. However, according to Blomberg and Hess (2005: 7), TWEED “is one of the richest and long-standing data sets available”. Yet a drawback with the dataset is that it only records acts of internal terrorism, and has a limited coverage. Users may therefore want to supplement the TWEED data with information from other sources, such as the MIPT Terrorism Knowledge Base and International Terrorism: Attributes of Terrorist Events (ITERATE; see Mickolus 2002 for details). See also Eck (2005) for an overview of datasets of conflict data.

Electronic resource

MIPT Terrorism Knowledge Base


Blomberg, S. Brock, and Gregory D. Hess. 2005. “From (no) butter to guns? Understanding the economic role in transnational terrorism”. Prepared for the World Bank Workshop on Security and Development, Washington D.C., 26-27 May 2005.

Eck, Kristine. 2005. A Beginner’s Guide to Conflict Data: Finding and Using the Right Dataset. UCDP Paper no. 1. Uppsala: Uppsala Conflict Data Program.

Engene, Jan Oskar. 2006. TWEED Code Book. Bergen: Department of Comparative Politics, University of Bergen.

Engene, Jan Oskar. 2007. “Five decades of terrorism in Europe: the TWEED dataset”. Journal of Peace research 44 (January): 109-121.

Mickolus, Edward F. 2002. “How do we know we’re winning in the war against terrorists? Issues in measurement”. Studies in Conflict and Terrorism 25 (3): 151-160.