In a report delivered at the ACSG’s 2025 Conference, TTS’s Dr. Sebastian Clifton and Dr. Angela Marsburg examined one of the more persistent beliefs in ability and behavioral assessments: That time of day and timing relative to deadlines significantly influence candidate performance.
Their study, reported at the conference and in this article, analyzed over 21,000 assessment records, making it one of the most robust local examinations of timing effects in the field to date.
A common belief with limited evidence
Drawing attention to evolving assessment modalities, especially asynchronous, mobile, and AI-driven platforms, our presenters noted that candidates today enjoy unprecedented autonomy over when and how they can complete their assessments.
Given this shift, IO Psychologists and assessment practitioners face a new responsibility: That of providing sound guidance, rooted in evidence, on how to perform at one’s best, especially in high-stakes assessment projects.
To this end, our team tested the assumption that candidates perform best on cognitive assessments in the morning, ideally during working hours. This is a position echoed by test publishers and many practitioners.
Study 1: Cognitive performance across timeframes
Study 1 analysed composite cognitive ability scores for over 19,000 candidates, examining:
- Morning vs. Afternoon completion
- Working hours vs. non-working hours
- Granular time segmentation: before work, morning hours, afternoon hours, and after hours
Key findings reported at the conference were:
- While statistically significant differences emerged (likely due to the large sample size), effect sizes were small in all cases.
- Candidates who completed assessments after working hours slightly outperformed those who did so during traditional work times, but only marginally (Cohen’s d = 0.23–0.27).
- Overall, and contrary to widely held beliefs, completing cognitive assessments in the morning offered no practical advantage to candidates.
Study 2: Personality profiles and weekday vs. weekend completion
The second study focused on a graduate population, comparing personality profiles of those completing assessments on weekdays versus weekends.
- Weekend completers scored higher on conscientiousness, especially on traits like being structured, detail-oriented, and dependable.
- Weekday completers showed modestly higher scores on traits related to sociability and liveliness.
- These differences, while statistically meaningful, were also only of moderate effect size, suggesting environmental or personality-based self-selection rather than causality.
Practical recommendations: Contextual flexibility over prescription
The presenters cautioned against rigidly enforcing specific assessment times. Instead, they recommended:
- Allowing candidates to choose their preferred assessment time, thus respecting individual circadian rhythms and productivity patterns.
- Running graduate assessment stages across both weekdays and weekends, as subtle personality-related self-selection may be occurring.
- Continuing to encourage candidates to complete assessments when they feel well-rested and prepared, rather than supporting a “morning is best” narrative.