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.

Quantitative methods have been used to: (1) better predict civil conflict onset; and (2) understand causal mechanisms to inform policy intervention and theory. However, an exploration of individual conflict onset cases illustrates great variation in the characteristics describing the outbreak of civil war, suggesting that there is not one single set of factors that lead to intrastate war. In this article, we use descriptive statistics to explore persistent clusters in the drivers of civil war onset, finding evidence that some arrangements of structural drivers cluster robustly across multiple model specifications (such as young, poorly developed states with anocratic regimes). Additionally, we find that approximately one-fifth of onset cases cannot be neatly clustered across models, suggesting that these cases are difficult to predict and multiple methods for understanding civil conflict onset (and state failure more generally) may be necessary.

The June 2016 Brexit referendum sent international shock waves, possibly causing adjustments in public opinion not only in the UK, but also abroad. We suggest that these adjustments went beyond substantive attitudes on European integration and included procedural preferences towards direct democracy. Drawing on the insight that support for direct democracy can be instrumentally motivated, we argue that the outcome of the Brexit referendum led (politically informed) individuals to update their support for referendums based on their views towards European integration. Using panel data from Germany, we find that those in favour of European integration, especially those with high political involvement, turned more sceptical of the introduction of referendums in the aftermath of the Brexit referendum. Our study contributes to the understanding of preferences for direct democracy and documents a remarkable case of how – seemingly basic – procedural preferences can, in today's internationalized information environment, be shaped by high-profile events abroad.

Societal attitudes toward gender roles in the workplace and politics play a central part in theorizing on the difficulty women face in achieving political equality, but shortcomings in the available data have prevented direct examination of many implications of these theories. Drawing on recent advances in latent-variable modeling of public opinion and a comprehensive collection of survey data, we present the Public Gender Egalitarianism dataset to address this need: comparable estimates of the public's attitudes on gender equality in the public sphere across more than one hundred countries over time. These Public Gender Egalitarianism scores are strongly correlated with responses to individual survey items and with women's rates of participation in the labor force and corporate boards. We expect that the Public Gender Egalitarianism data will become an invaluable source for broadly cross-national and longitudinal research on the causes and consequences of collective attitudes toward gender equality in politics and the economy.

In path-breaking work, Weingast et al. argue that there is a positive relationship between legislature size and inefficiency in public expenditures. Their proposition is currently known as the ‘law of 1/n’ and has been widely debated in political science and public administration. However, recent studies have questioned the validity of the theory. In this letter, we conduct the first meta-analysis that assesses the generality of the ‘law of 1/n’. Based on a sample of thirty articles, we find no robust evidence suggesting that legislature size has either a positive or a negative effect on government budgets. Yet, the aggregate results mask considerable heterogeneity. Our findings provide moderate support for the ‘law of 1/n’ in unicameral legislatures and in upper houses, but they also indicate that studies using panel/fixed-effects models or regression-discontinuity designs report negative public spending estimates. We find only limited evidence that electoral systems impact public spending, which suggests that proportional representation systems may not be more prone to overspending than majoritarian ones.

Are there electoral consequences or benefits for legislators who deviate from the party line? We answer this question with data from individual-level vote choice and constituency-level electoral results in the UK for the last two decades. Exploring the variations in voting patterns over time with a panel-regression approach, we find results that are most compatible with the null hypothesis, that is, that dissent by legislators is neither rewarded nor punished in elections. These results call into question the degree to which voters know and/or care about legislative dissent in parliament.

Why do politicians and policymakers not prioritize pro-immigration reforms, even when public opinion on the issue is positive? This research note examines one previously overlooked explanation related to the systematically greater importance of immigration as a political issue among those who oppose it relative to those who support it. To provide a comprehensive empirical assessment of how personal immigration issue importance is related to policy preferences, I use the best available cross-national and longitudinal surveys from multiple immigrant-receiving contexts. I find that compared to pro-immigration voters, anti-immigration voters feel stronger about the issue and are more likely to consider it as both personally and nationally important. This finding holds across virtually all observed countries, years, and alternative survey measures of immigration preferences and their importance. Overall, these results suggest that public attitudes toward immigration exhibit a substantial issue importance asymmetry that systematically advantages anti-immigration causes when the issue is more contextually salient.

We know from election studies which demographic characteristics best predict vote choice, but we know far less about how citizens perceive their similarity to one another in terms of these characteristics. Previous research suggests that such perceptions may be crucial for the politicization of social identities and the emergence of political identities. I present results from a novel measurement strategy where respondents are presented with the profiles of two fellow citizens, including several demographic attributes. Respondents are asked which of the two they perceive themselves to have more in common with in terms of politics. Respondents' implicit trade-off of different demographic similarities allows me to measure the relative strength of their perceived political similarities. I find an important role for shared ethnicity, noticeably surpassing shared social class, age and education. Finally, I find that shared ethnicity receives substantially more weight among 2017 Conservative and 2016 Leave voters than among Labour and Remain voters.