The rigor of occupation-based standardized assessments that rely on observational scoring procedures depends on proven reliability among test administrators. This study measured interrater reliability of the Cognitive Performance Test (CPT), a standardized, occupation-based assessment that measures cognitive- functional capacity in older adults with neurocognitive disorders. To capture a range of experience among test administrators, two sets of raters-four expert and three novice-scored video recordings of 10 patients administered the CPT. Interrater reliability results were strong among all raters (intraclass correlation coefficient [ICC] 5 .93), with expert raters (ICC 5 .97) yielding higher coefficients than novice raters (ICC 5 .93). Spearman's r correlation coefficients were high among all raters (rs 5 .92-1.00). Practitioners can be confident that results of the CPT give accurate and consistent information to the health care team, family members, and patients when administered with fidelity using standardized protocols.