Validating the Online Circle Test (OL-CT): cross-format equivalence, one-week reliability, and contextual stability in Japanese undergraduates

BACKGROUND: The Circle Test is a drawing-based task for assessing time perspective, but conventional paper-and-pencil administration requires substantial human resources for scoring and quantification, limiting its scalability for large or remote surveys to be conducted. We developed an online web-based circle test with automated scoring and evaluated its validity and reliability. METHODS: Thirty-six Japanese undergraduates completed both the Online Circle Test (OL-CT) and paper-and-pencil Circle Test (PP-CT) in a counterbalanced crossover design (Visit 1) and repeated the OL-CT after 7-9days either in the laboratory or at home (Visit 2). Continuous indices included log-transformed absolute and proportional areas, and categorical indices included temporal dominance and temporal relatedness. Analyses evaluated (a) cross-format equivalence between PP-CT and OL-CT, (b) one-week test-retest reliability of the OL-CT, and (c) contextual stability across laboratory versus home administration. RESULTS: Cross-format equivalence was moderate for log-transformed absolute areas (ICC = 0.73-0.77) but excellent for proportional areas (ICC = 0.89-0.90). The categorical agreement was high (88.9%), with no systematic category shift. One-week test-retest reliability was moderate-to-excellent for absolute areas (ICC = 0.69-0.89) and excellent for proportional areas (ICC = 0.93-0.95). Categorical stability was also high (temporal dominance: 91.7%, κ = 0.88; temporal relatedness: 86.0%, κ = 0.76). The OL-CT indices did not differ between the laboratory and home retesting contexts. CONCLUSION: In this Japanese undergraduate sample, the OL-CT showed promising preliminary psychometric properties as a digital adaptation of the Circle Test, particularly when proportional indices are treated as the primary continuous outcomes. The findings support its potential use as a scalable tool for assessing time perspective across formats, over a one-week interval, and across testing contexts.