By Tonita E. Wroolie, Ph.D. Clinical Psychologist
The terms capacity and competency are often used interchangeably to declare ability. However, there are differences. Competency is categorical in nature; one either is or is not competent. A person is competent if he or she possesses certain qualities or characteristics that allow him or her to function in a particular circumstance, such as having job skills needed for employment. In court, competency is the ability to testify, which is dependent upon an individual’s overall ability to understand and reason adequately, and is determined by the court.
Capacity, on the other hand, refers to specific abilities and may change over time due to delirium, medications, course of an illness and/or treatment effects. Capacity may be executional or decisional. Executional capacity is the ability to perform certain skills such as, live independently, manage one’s own finances, and drive a vehicle. Decisional capacity means that one is capable of understanding relevant information and appreciating reasonably foreseeable consequences when making a decision. Decisional capacities include, but are not limited to, making a will or executing a power of attorney (testamentary capacity), giving a gift (donative capacity), capacity to execute a contract or transfer property (contractual capacity), consent to medical care, and consent to engage in sexual activity. Typically a physician or psychologist evaluates an individual for capacity, using either subjective opinion based on expertise or objective evidence based on a formal evaluation.