A study performed by Makel et al. (2012) looked at the prevalence of replications in the field of Psychology in a time-period from 1950-2012. At the time they found an increase in replication...Show moreA study performed by Makel et al. (2012) looked at the prevalence of replications in the field of Psychology in a time-period from 1950-2012. At the time they found an increase in replication studies over time. Besides the increase they also found a possibility of experimenter bias when there was an overlap in authors. This thesis is a conceptual replication study of Makel et al. (2012) focussing on the possible prevalence of experimenter bias in replication studies based on an overlap of authors. It was expected that there would be more successful results when there is an overlap in authors. A difference of 19.04 was found on the percentage of successful results between an overlap in authors and unique authors. This indicates that there is a relation between overlap in authors and successful results, however to determine if this relation is caused by experimenter bias, more research is needed.Show less
This research was conducted as a conceptual replication of the study by Makel et al. (2012), in order to compare the success rate of two different types of replication (direct and conceptual)....Show moreThis research was conducted as a conceptual replication of the study by Makel et al. (2012), in order to compare the success rate of two different types of replication (direct and conceptual). Additionally, Hüffmeier et al. (2016)’s typology was used (exact, close, constructive, conceptual in lab, and conceptual in field types of replication), in order to achieve a more detailed understanding of the different types of replication. The expectation of the study was to find a higher success rate of lower replication types: close, constructive, conceptual in lab, conceptual in field (Hüffmeier et al., 2016) and conceptual (Makel et al., 2012), in comparison to the higher replication types: exact (Hüffmeier et al., 2016) and direct (Makel et al., 2012). After an advanced search on Web of Science for articles in the psychological field published between 2000 and 2020 using the term “replicat*”, a random sample of 5000 articles was selected, that was manually coded by 14 people. The main findings showed that conceptual replications had a lower success rate than direct replications. However, the results based on the replication types in Hüffmeier et al. (2016) indicated that conceptual in lab and conceptual in field replications had the highest success rates, followed by exact replications. This demonstrated the importance of the order of studies in yielding research quality. Additionally, looking at the success rates, it can be concluded that confidence in findings can still be achieved in lower types of replication, despite of changing the methodology of the original article.Show less
