Impact of Phone Collection on Student Performance: Insights from a Large-Scale Trial in Odisha
At the onset of lectures across 10 higher education institutions in Odisha, India, students in one group were required to place their phones in wooden boxes, while another group retained their phones under the usual classroom rules. This seemingly simple intervention aimed to remove a recurring distraction—checking phones every few minutes—without any technical complexity.
The randomized trial, spanning the spring 2024 semester, involved 16,955 undergraduate and postgraduate students, making it significantly larger than typical phone-related classroom attention studies. The results showed a modest but meaningful improvement in grades following the phone collection policy.
After adjusting for students’ prior academic performance, researchers found an average increase of 0.086 standard deviations in GPA for those subjected to phone collection. Notably, students with lower prior GPAs experienced a gain nearly twice as large, at 0.161 standard deviations. This suggests that the intervention helped especially those who struggled academically, although the effect was not uniform for every student or institution.
The Design and Scope of the Experiment
The study was conducted by Alp Sungu (Wharton), Pradeep Kumar Choudhury (Jawaharlal Nehru University), and Andreas Bjerre-Nielsen (University of Copenhagen), with findings detailed in a working paper. The intervention randomly assigned entire department-and-semester cohorts within each institution to either deposit phones in wooden boxes made from recycled materials or continue as usual. This cohort-level randomization ensured students faced consistent phone policies across their courses during the semester.
Importantly, the experiment altered access to phones during lectures, not ownership or exam conditions—phones were already excluded from final assessments. Teachers enforced collection rules but were not prohibited from using their own phones. Students with emergency or caregiving needs could seek exemptions, ensuring fairness and accommodation.
This approach acknowledged the social classroom environment, recognizing that collective adherence to a phone policy could shift peer behavior, teacher engagement, and overall classroom norms, rather than focusing solely on individual self-control.
Understanding the Measured Effect: What 0.086 Standard Deviations Mean
The reported average GPA increase of 0.086 standard deviations is statistically significant, with a 95% confidence interval from 0.015 to 0.157. However, this figure is not a percentage increase or a direct grade point gain; rather, it measures the effect relative to variability in grades across institutions with different grading systems.
For context, a Wharton summary rounded the effect to roughly 0.07 standard deviations, highlighting the modest scale of improvement. Alternative statistical models produced estimates ranging from 0.034 to 0.112, with the most rigorous student fixed-effects model yielding the smallest, statistically insignificant effect. This variation underscores the importance of interpreting the average effect cautiously rather than as a precise figure.
Differential Benefits Among Student Groups
While the overall effect was modest, subgroup analyses revealed that students with lower prior GPAs gained approximately 0.161 standard deviations, nearly double the average benefit. First-year students also benefited more substantially, with an estimated increase of 0.142 standard deviations. Non-STEM students showed a modest gain of 0.097 standard deviations, whereas STEM students exhibited a smaller, statistically unclear improvement.
Such subgroup findings suggest that students with weaker study habits or academic preparation may find greater benefit from reduced phone distractions. In contrast, higher-performing students might be less affected by phone access due to established routines or academic confidence.
These insights emphasize that averaging effects across a heterogeneous population can mask meaningful improvements experienced by specific groups.
Classroom Dynamics Beyond Student Attention
The researchers complemented grade data with attendance records, two survey waves, and 7,797 unannounced classroom spot checks conducted discreetly through doors or windows. Observers noted less phone use among students in treatment classrooms, fewer off-topic conversations, and reduced disruptive behavior overall.
Interestingly, teachers in phone-collection classrooms were observed using their own phones less often and appeared more engaged with teaching materials, despite not being subject to the phone collection rule. This suggests that enforcing the policy may have fostered a more focused classroom atmosphere benefiting both students and instructors.
However, some observers noted increased signs of apparent distraction, possibly due to students shifting to daydreaming or other non-phone-related diversions. Students themselves did not report heightened distraction, indicating that the effect on attention may be complex and not solely dependent on phone presence.
It’s important to recognize that spot checks relied on brief external impressions and that observers might infer group assignment based on visible phone collection, limiting the objectivity of these behavioral measures.
Student Sentiments and Broader Effects
Students exposed to the collection policy reported growing support for it over time, recognizing more benefits and expressing less preference for unrestricted phone use. Yet, the intervention did not universally improve student wellbeing or motivation. Minor increases in fear of missing out were observed, but no significant changes occurred in overall digital usage, online harassment, or attendance rates.
Thus, the improved academic performance cannot be explained by increased class attendance or reduced phone possession on campus. Instead, the intervention’s impact appears focused on in-class attention and behavior rather than broader lifestyle changes.
Comparatively, a previous randomized experiment cited by Silicon Canals found that even limited phone use during meals reduced reported enjoyment. Together, these studies illustrate how phone access—even for brief moments—can influence experience and outcomes in different settings.
Possible Mechanisms and Limitations
The physical collection of phones likely reduces distractions by removing notifications, preventing impulsive checking, and eliminating repeated decisions to resist temptation. Additionally, visible collection may create social norms that discourage phone use, reinforcing collective focus.
In this sense, the wooden box functions as a commitment device, allowing students to make a single upfront decision rather than battling ongoing impulses. However, the trial was not designed to isolate how much of the effect was due to temptation reduction, peer influence, or teacher behavior.
Moreover, the intervention tested a specific, enforced procedure. Asking students merely to silence phones or instituting voluntary phone-free sections would likely yield different results. The physical visibility, consistency, and enforcement of collection are critical components of the treatment.
Logistical challenges limited the study’s planned scope; only 10 of the intended 18 institutions completed the experiment, and baseline surveys or phone-tracking apps could not be implemented pre-treatment. These constraints reduced opportunities to analyze individual device use patterns and some student-level differences.
The full findings are detailed in a 63-page preregistered, institutionally reviewed working paper, which remains under peer review and may be refined further.
What This Study Establishes and Its Practical Implications
The randomized design strengthens causal claims beyond correlational studies that compare frequent and infrequent phone users. Cohorts randomly assigned to phone collection performed better academically than similar cohorts without the intervention.
However, generalizing these results to other contexts requires caution. Different educational settings—such as secondary schools, digitally integrated courses, hybrid learning environments, or institutions with alternative phone policies—may experience varying outcomes.
Implementation fidelity is also crucial. The study’s success depended on providing boxes, clear exemptions, and teacher enforcement. Inconsistent or nominal phone bans are unlikely to replicate these effects.
Finally, GPA improvements do not capture all costs or benefits. Students may need phone access for legitimate reasons; instructors might integrate phones into teaching; and collection introduces logistical concerns and potential friction. These factors mean the study does not prescribe a universal policy but rather offers evidence that removing immediate phone access can yield small academic benefits, especially for students starting with weaker performance.
Overall, the trial highlights that while the average effect is modest, understanding who benefits most enriches how educators might consider phone policies in classrooms.
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