This study explores how researchers’ analytical choices affect the reliability of scientific findings. Most discussions of reliability problems in science focus on systematic biases. We broaden the lens to emphasize the idiosyncrasy of conscious and unconscious decisions that researchers make during data analysis. We coordinated 161 researchers in 73 research teams and observed their research decisions as they used the same data to independently test the same prominent social science hypothesis: that greater immigration reduces support for social policies among the public. In this typical case of social science research, research teams reported both widely diverging numerical findings and substantive conclusions despite identical start conditions. Researchers’ expertise, prior beliefs, and expectations barely predict the wide variation in research outcomes. More than 95% of the total variance in numerical results remains unexplained even after qualitative coding of all identifiable decisions in each team’s workflow. This reveals a universe of uncertainty that remains hidden when considering a single study in isolation. The idiosyncratic nature of how researchers’ results and conclusions varied is a previously underappreciated explanation for why many scientific hypotheses remain contested. These results call for greater epistemic humility and clarity in reporting scientific findings.

Empirical evidence has consistently shown that political participation is positively related with socioeconomic background. Furthermore, recent research suggests that children who come from low status families are already less willing to get politically involved. The present paper aims to analyze the possible impact that schools can have in mitigating the effect of parents' socioeconomic status on students' expected electoral participation, focusing on two variables: civic knowledge and classroom climate. The analyses are based on a series of multilevel models using Chilean data of the International Civic and Citizenship Education Study 2009. The results support the influence of students' socioeconomic background on expected electoral participation. Furthermore, civic knowledge and classroom climate show a positive and similar influence on students' expected participation. However, classroom climate appears less affected by students' background than civic knowledge, opening the discussion about which strategy should be emphasized when aiming to mitigate the political participation gap.

Though the concept of social justice is widely used in the social sciences, we know little about the amount of income inequality that is perceived as just and why perceptions vary across social contexts. In this paper, we argue the ways people define the causes of poverty are related to how they perceive and justify existing income inequality. We examine internal and external attributions of poverty using survey data from the 2006 International Social Justice Project (ISJP). We compare two culturally and structurally distinct regions—East and West Germany. The results support our hypothesis that the amount of income inequality people perceive as just is related to how they explain the causes of poverty, that is, internal and/or external attributions. Poverty attributions are crucial mediators and explain contextual differences in the perceived justice of income inequality between East and West Germany.