Reasoning ability in older adults measured through letter and number series

Letter series and number series tests, consisting of items based on identical rules, were administered in a counterbalanced design to 58 persons (46 women and 12 men) between the ages of 61 and 88 years to determine their relative efficacy (relative difficulty and acceptability) as measures of inductive/deductive reasoning ability. Results indicated that letter and number series tests, in which each item in one has a same-rule counterpart in the other, were not equivalent in regard to their relative difficulty or popularity among the elderly. The number series test was significantly (p 0001) easier and more popular than its letter series counterpart. Some of the implications of these findings for assessing reasoning ability in the elderly were specified.