Experimental Design
The aim is to analyze whether knowledge of their percentile rank throughout the semester among students at Universidad Rey Juan Carlos in Madrid improves their final course grades. To achieve this, a database has been compiled over several semesters, comprising a sample of over 600 students. The class was divided into a treatment group, who received their percentile rank along with their midterm grade, and a control group, who only received their exam grade. To understand the sample, questionnaires were administered at the beginning of the course, asking for relevant data and their estimated final course grade. Additionally, at the end of the course, another questionnaire was administered to determine whether awareness of their percentile rank stimulates additional motivation or, conversely, leads to overconfidence.
As a post-trial update, we wish to register that, in addition to the pre-specified average treatment effect analyses, we have conducted a series of heterogeneity analyses. These include subgroup interactions by baseline performance (low initial grades), socioeconomic indicators (scholarship status, low parental education), self-reported expectations, relative age (quarter of birth), gender, and academic history (number of enrollments, exam round, and age). We also explored variation across different PLAN assignments and interactions with resource indicators such as car ownership, driving license, and private classes. These analyses were performed using the same specifications as the main models, with robustness checks including PLAN fixed effects, individual controls, and alternative outcome definitions (e.g., grade improvements between midterm and final exam).
The results indicate that average treatment effects remain small and mostly insignificant, but important heterogeneity emerges. In particular, students with weaker academic histories (older, more exam attempts, or multiple prior enrollments) tend to benefit more from percentile feedback, consistent with a motivation-through-information mechanism. Similarly, students with lower expectations or disadvantaged family backgrounds display differential responses, though often imprecisely estimated. These findings, while exploratory and not pre-registered, enrich the interpretation of the intervention’s impact and highlight the importance of considering subgroup variation in the design of information-based educational interventions.