Observing many researchers using the same data and hypothesis reveals a hidden universe of uncertainty

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.

Social Support Benefits Psychological Adjustment of International Students: Evidence From a Meta-Analysis

A growing body of literature is exploring the link between social support and international students’ psychological adjustment. So far, however, there has been no systematic assessment of the overall relationship, and no indication which types and sources of social support may be most strongly associated with psychological adjustment. Our meta-analysis of 257 effect sizes across 76 studies fills this gap and assesses (a) the magnitude of the overall association between social support and international students’ psychological adjustment, (b) how different types (subjective, objective, and mixed) and sources (host, conational, international, mixed, and unspecified) of social support moderate the relationship between social support and psychological adjustment, and (c) whether the relationship between social support and psychological adjustment holds across different operationalizations of psychological adjustment. We find a positive overall association ( r = .20, 95% confidence interval [CI] = [0.16, 0.23]) between social support and international students’ psychological adjustment. Types and sources of social support matter as well: Subjective social support relates more strongly to psychological adjustment than objective social support. The data revealed that only support from mixed sources (i.e., not distinguishing between internationals, host, or conationals) is associated with a stronger effect of social support than support from conationals or from fellow international students (compared with support from host sources). We find no differences in the relation between social support and positive or negative adjustment. We outline recommendations for future research based on the meta-analysis.