What is a capacity evaluation? 

Capacity refers to an assessment of an individual’s psychological abilities to form rational decisions, specifically the individual’s ability to understand, appreciate, and manipulate information, and form rational decisions. Capacity is determined by physician often (although not exclusively) by a psychiatrist, and not the judiciary. It is different from competency, which is a legal term referring to “having sufficient ability… possessing the requisite natural or legal qualifications” to engage in a given endeavor. The determination of incompetence is a judicial decision, i.e., decided by the court.

There are four key elements in documenting a decision about capacity:

1. Ability to Evidence a Choice
   Capacity to evidence a choice can be tested by asking patients who have been informed about their medical condition and proposed interventions to respond to what they have been told.
2. Ability to Understand Relevant Information
   The ability to understand relevant information can be best assessed by asking patients to disclose her understanding of the proposed treatment intervention or diagnostic procedure. It is best to ask them to paraphrase it.
3. Ability of Appreciate the Situation and Its Likely Consequences
   Assessment of the patient’s ability to appreciate is not based upon comparison of the patient’s express wishes against the standard of what most reasonable persons would endorse in that situation.
4. Ability to Manipulate Information Rationally
   This component does not focus on the ultimate decision that the patient reaches, but rather the process with which he or she arrives at decisions.