Functional Approach to Capacity

A person’s capacity shall be assessed on the basis of his or her ability to understand, at the time that a decision is to be made, the nature and consequences of the decision to be made... in the context of the available choices at that time.

Assisted Decision-Making (Capacity)
Act 2015, Section 3(1)

A person has the right to self-determine, to respect for their autonomy and to make decisions about matters which affect their own lives. One of the key principles of the Assisted Decision-Making (Capacity) Act 2015 is that a person is presumed to have capacity to make their own decisions, unless it is shown otherwise based on a functional approach. An assumption about a person’s capacity cannot be made based on a disability, an illness or condition.  

A functional approach recognises that decision-making capacity can fluctuate and it is specific to the particular decision. Functional capacity is ‘issue specific and time specific’. The decision-making process has levels of complexity based on the type and urgency of the decision, and a person’s decision-making capacity can be impacted by many factors. While a person may have difficulty or lack capacity to make some types of decisions it does not mean that the person lacks capacity to make other types of decisions. It also recognises that a person may lack decision-making capacity at one time, but not lack capacity if presented with the same decision at another time. Functional capacity considers the person’s process of making a decision, and not the outcome of the decision itself. 

Taking a functional approach to capacity means that a person should be supported to maximize their ability to make the decision themselves, or to maximize their participation in the decision-making process. If a person’s capacity is in question or the person lacks capacity to make the specific decision the ADM (Capacity) Act 2015 provides for a range of decision-making supporters (Interveners)to provide the appropriate level of support needed for the person to exercise their decision-making autonomy.  

Functional Approach - Lack Of Capacity

Decision-Making Capacity

  • A person is not considered to be unable to understand the relevant information if they are able to understand an explanation of it given in a way that is appropriate to their circumstances and communication means. 
  • A person only needs to retain the information long enough to make the decision, the length of time of retention is not relevant
  • Functional capacity is issue specific and time specific
    • “The fact that a person lacks capacity in respect of a decision on a particular matter at a particular time does not prevent him or her from being regarded as having capacity to make decisions on the same matter at another time.” ADM (Capacity) Act 2015, Section 3(5)
    • “The fact that a person lacks capacity in respect of a decision on a particular matter does not prevent him or her from being regarded as having capacity to make decisions on other matters.”ADM (Capacity) Act 2015, Section 3(6)
  • Relevant information includes
    • information on the reasonable foreseeable consequences of each available choice at the time
    • information on the consequences of not making the decision
  • The person does not need to understand all information related to the decision, only the relevant/salient information
  • The person can communicate their decision by any means – talking, writing, sign langaguge, drawing, assistive technology

Watch: Functional approach to capacity by mary condell, sage advocacy legal advisor