The indicator (the Wikipedia Dispute Index) considers the frequency of disputed pages linked to a country compared to that expected on average (see Methods
). The world heat-map constructed using this measure () suggests that disputes in Wikipedia do correlate with regional instabilities across the world. Of the 138 (of 497) countries/regions with sufficient data to compute the indicator with confidence, the most disputed are parts of the middle east followed by other regions such as Kosovo, Bosnia & Herzegovina and North Korea (; Table S1
). At the other extreme, countries in North America and Western Europe are the least disputed, with most other countries occupying a middle range.
Mercator projection of the world colored according the Wikipedia dispute index.
There are certain exceptions, such as Poland, Peru or Romania that have fewer disputes than might be expected. Inspection suggests that these outliers are likely to do with fewer pages in English than languages of the region; the Polish Wikipedia is the fourth largest, the Spanish, seventh. The picture for Peru (and the rest of South America) changes when one considers the Spanish version of Wikipedia (Figure S1
), though only the English Wikipedia covers the globe to a useful degree (138 countries compared to 24 for German, 30 for French, 50 for Spanish). There are also many countries (see grey in and Figure S1
) where there are currently too few pages or disputes to compute our measure with confidence. A consideration of other languages could lead to a more comprehensive list, though lack of internet access locally and/or diaspora in better connected countries could be an additional limitation (e.g. see Africa in and Figure S1
The biggest contributors to the indicator tend to be disputes over current or historical events or individuals that vary according to different political views. However, other contributing factors are less intuitive, for instance, the disputed page “Adultery” is linked to several Middle-eastern and South American countries. There are also what appear to be spurious links, or those that can only loosely be linked to the countries of interest. For example, the page related to the football club “FC Aarau” was disputed in late 2010, and linked to Moldova owing to a Moldovese player. However, such links appear to be exceptions forming a background of disputes that likely contributes equally to all countries (see Methods
There are many other governance, economic or political indicators in common use (e.g. 
). These are subject to criticisms such as the inability to compare changes over time, biases towards particular experts' opinions, or disparate and/or subjective data sources 
. Our dispute index agrees with other indicators of political stability/instability 
about as well as they agree with each other (; Figure S3
) and the correlation improves with increasing data stringency (Figure S2
), suggesting that index should improve as Wikipedia grows in size. Considering the components of known indicators (see Methods
), the best agreement to our indicator are to the “Underlying Vulnerability” metric devised by the Economist Intelligence Unit 
, and to “Voice and Accountability” from the World Bank Governance Indicators 
), which are perhaps the metrics most similar to the tension captured within Wikipedia disputes. The other indicators vary considerably in what they measure, and how they are calculated, but typically they are based on combining various political or economic metrics, questionnaires and opinions. The dispute index is not free from subjectivity as it is derived from a web site with thousands of contributors with differing opinions. However, it is easy to calculate, and does not rely on complex data gathering or the solicitation of experts. It also changes over time seemingly in concert with major world events (see below).
Figure 2 Plots comparing the Wikipedia Dispute Index (X axis) to a) the World Bank Policy Research Aggregate Governance Indicator (WGI) for political stability  (R=−0.781), and b) the Economist Intelligence Unit 2009 political instability (more ...)
A natural question is how long this indicator will be useful in the wake of the constant editing and conflict resolution efforts of contributors. There are pages that are difficult to resolve despite months or even years of discussion, but many are resolved. For instance, the page named “Islam and Antisemitism” lost its disputed status in 2010, whereas the page “Demographics of Kosovo” created in February 2007 picked up a dispute in mid-2008 and remains disputed at the time of writing. However, despite many changes in the pages in dispute, the rankings are relatively stable over time, for instance when considering the G8 countries (). This is remarkable considering the drastic changes in the underlying disputed pages: on average, only 7.8% of disputed pages linking to countries were common when comparing datasets for August 2010 and April 2007.
Values of the dispute index over a 3 year period for a) the G8 countries, b) countries in the Caucasus, c) the Balkans and d) Nordic countries.
There are nevertheless revealing changes over the time period we studied (). For instance for the Balkan or Caucasus regions, changes appear roughly in line with political events: values for South Ossetia, Abkhazia and Georgia increased during and after the 2008 war; Kosovo increased after the 2008 declaration of independence. Trends go both ways: for instance Slovenia shows a steady decrease correlating perhaps with EU integration (its value goes towards those for Western EU members). The indicator for Iceland increased slightly relative to other Nordic countries during the recent Economic crisis (a slight upward trend is also seen recently for Greece in the Balkans plot). However, such changes are not always apparent: values for Middle Eastern and North African countries, for example, were stable over the recent revolutionary period. To provide the means to chart changes over time, we have created a web resource with a version of the map in and cross references that will be updated weekly (see www.disputeindex.org
It is remarkable that so simple a metric can agree so well with more complex measures of political and economic stability. We do not mean to suggest that this indicator could replace existing metrics since the issues mentioned above related to sparse data and language currently preclude this possibility. However, this work does demonstrate that information contained within resources like Wikipedia can be used in interesting and useful new ways that can ultimately complement more arduous metrics. Further systematic analyses of vast information networks now available on the Web with the tools and expertise of multiple disciplines will clearly continue to impact on many subjects.