Global Cognitive Index

Statistics and Comparisons

Reference groups and provisional standardized scores

Japanese and English norms are built separately and only from attempts with matching plan, age band, assessment engine, question bank, and scoring version. The core reference sample consists of first attempts by consenting participants aged 8 or older, with verified guardian consent additionally required for participants under 18. In addition to technical inconsistencies, an attempt is excluded when low score rate and implausibly short response times occur together across enough answers and multiple Parts. Low performance alone or fast performance alone is not excluded.

The server does not trust a browser-supplied total. It rescales every response against the assigned Form's scoring manifest. Administrators generate a draft norm and review sample size, mean, standard deviation, Form differences, item facility, and corrected item-total correlations before approval.

Without an approved norm, the result remains a raw-score profile. After approval, the displayed score is a provisional transformation with mean 100 and standard deviation 15, while the percentile is the empirical rank in the reference sample. GCI is not a formal clinical IQ assessment.