Understanding your FogScore

Your overall FogScore Performance Index and four domain scores range from 0 to 100. Higher scores indicate stronger performance on the specific tasks completed. This is a fixed task-performance scale, not a percentile rank or a percentage of brain function.

What contributes to each score?

• Attention: target discrimination and consistency of response times during sustained attention.
• Memory: backward digit span, verbal paired-associate recognition, and visual paired-associate recognition, equally weighted.
• Processing speed: correct symbol matches during the first 90-second matching task and Trail Making A completion time, equally weighted.
• Executive tasks: Trail Making B completion time, including time spent correcting errors.

The overall index is the average of these four domains, with each contributing 25%. A complete, valid six-task battery on a computer with keyboard and pointer is required for the overall index. Missing measurements are never filled in.

How the fixed scale works

The scale is anchored to published TestMyBrain task reference datasets for adults aged 18–89 using keyboard or mouse. Development records determined fixed lower and upper anchors at the 2.5th and 97.5th quantiles. Separate held-out records were used to evaluate the resulting scale. Times and response-time variability use logarithmic scaling; other measurements use linear scaling. Values beyond the anchors reach 0 or 100; their raw measurements are still shown.

Age and your personal baseline do not change the score calculation. The same valid measurements and scoring version produce the same score. Reference samples are convenience samples, not a representative clinical population. Published task reference data do not establish clinical validity of the FogScore index.

Comparing sessions

Compare the same scoring version and similar testing conditions. Practice, fatigue, sleep, distractions and device differences can affect performance. The first two comparable sessions on separate dates can provide a numerical baseline. Changes are numerical observations; no reliable-change threshold, diagnosis, treatment-effectiveness or recovery claim is assigned. Overall and domain test–retest reliability have not been established for this combined battery.

Sources and permissions

Reference data: The Many Brains Project, Inc. and McLean Hospital; adapted under CC BY-SA 4.0. Tasks: GNU LGPLv3. Published datasets · Task source and credits.

Scoring version: fogscore-reference-2.0.0.

FogScore does not diagnose, treat, cure or prevent a medical condition.