Conceptual replication study of fifteen JDM effects: Insights from the Polish sample

We conducted pre-registered replications of 15 effects in the field of judgment and decision making (JDM). We aimed to test the generalizability of different classical and modern JDM effects, including, among others: less-is- better, anchoring, and framing to different languages, cultures, or current situations (COVID-19 pandemic). Replicated studies were selected and conducted by undergraduate psychology students enrolled in a decision-making course. Two hundred and two adult volunteers completed an online battery of replicated studies. With a classical significance criterion (p < .05), seven effects were successfully replicated (47%), five partially replicated (33%), and three did not replicate (20%). Even though research materials differed from the originals in several ways, the replication rate in our project is slightly above earlier reported findings in similar replication projects. We discuss factors that may underlie replication results (success vs. failure). We also stress the role of open science practices such as open data, open research materials, pre-registration, and registered reports in improving the replicability of results in the JDM field.