Researchers have long studied how the ideology of political leaders affects policymaking and social welfare. The limited coverage of cross-country ideology datasets, however, has meant that researchers have mainly focused on Organisation for Economic Co-operation and Development (OECD) countries. This letter therefore presents the Global Leader Ideology dataset, which vastly expands the scope of previous datasets by classifying chief executives as leftist, centrist, rightist or non-ideological in 182 countries annually from 1945 or independence to 2020. The letter describes the dataset's contents and coding, compares it to existing datasets, and illustrates its uses by exploring how the ideologies of political leaders differ around the world and over time. The letter thereby outlines a research agenda on the global causes of chief executives' ideologies and their effects on policies and socio-economic outcomes.

How can one assess which countries select more experienced leaders for the highest office? There is wide variation in prior career paths of national leaders within, and even more so between, regime types. It is therefore challenging to obtain a truly comparative measure of political experience; empirical studies have to rely on proxies instead. This article proposes PolEx, a measure of political experience that abstracts away from the details of career paths and generalizes based on the duration, quality and breadth of an individual's experience in politics. The analysis draws on a novel data set of around 2,000 leaders from 1950 to 2017 and uses a Bayesian latent variable model to estimate PolEx. The article illustrates how the new measure can be used comparatively to assess whether democracies select more experienced leaders. The authors find that while on average they do, the difference with non-democracies has declined dramatically since the early 2000s. Future research may leverage PolEx to investigate the role of prior political experience in, for example, policy making and crisis management.

Recent theories on the causes of war focus on how institutional and structural factors shape leaders’ decisions in foreign policy. However, citizens, policy-makers, and a growing number scholars argue that leaders’ background experiences may matter for both domestic and foreign policy choices. This article contributes to an emerging body of scholarship on leaders in international relations by showing how personal attributes influence the initiation of militarized disputes. Based on the soft power theory of international experiences and the impressionable-years hypothesis of socialization, I theorize that leaders with the experience of attending a university in a Western democratic country should be less likely than non-Western-educated leaders to initiate militarized interstate disputes. I test this proposition by employing a new dataset, building on Archigos and LEAD, that includes background attributes of more than 900 leaders from 147 non-Western countries between 1947 and 2001. The results strongly support the hypothesis, even when accounting for leader selection, time-variant country and leader-level controls, other leaders’ background characteristics, and country and year fixed effects. This finding lends credence to the soft power thesis of academic institutions on international sojourners, and highlights the value of considering leaders’ experiences in analyses about international relations.