Chapter 5: Best Interests – a Standard for Decision-making

Chapter 5 is in two sections:

  1. The absence of a “best interests” standard for decision-making in the PPPR Act and in the HDC Code.

  2. B. The evolution of the common law and codification of the best interests standard for decision-making
    under s 4 of the Mental Capacity Act (MCA).
  1. The MCA has a statutory “best interests” standard. It applies where a person takes actions or decisions on behalf of another person who lacks capacity and is “unable to make a decision”, as defined in sections 2 and 3 of the MCA.633 A “checklist” in s 4 provides a process for assessing the person’s best interests (the best interests assessment) and sets out matters that the substitute decision-maker (the decision-maker) must consider. These matters include the aim that the person with impaired capacity should participate in determining their best interests, recognising the person’s present and past wishes and feelings, and acknowledging the beliefs and values that would have likely influenced their decision if they had capacity.

  2. Under the MCA, the concept of best interests therefore provides a framework for decision- making on behalf of people with impaired capacity. Previously, the law focused mainly on the autonomy of people with capacity, such as their right to refuse medical treatment, rather than on decision-making for people who could not make autonomous decisions.634 As discussed in Chapter 2,635 this best interests framework is compatible with supported decision-making because it requires participation by the person with impaired capacity where possible, and it is an appropriate approach to decision-making for people who cannot make decisions for themselves. This approach also recognises that, even if a person is unable to make a legally binding decision with support, their likely will and preferences remain central to the decision- making process: capacity is not an off-switch to a person’s rights and freedoms.636

  3. Best interests guides substitute decision-making and is often contrasted to the notion of substituted judgment. While the former has traditionally been viewed as an objective standard, the latter is more subjective because it instructs the decision-maker to make the decision that the person would have wanted if they had capacity to do so. It has been preferred by courts in the United States.637 It is considered to uphold the person’s autonomy to a greater degree. Both approaches have their challenges.638 The statutory standard in the MCA can be regarded as a hybrid approach, as a subjective element was introduced that was previously absent from the common law’s approach to substitute decision-making.

  4. New Zealand’s legal framework provides no such comprehensive standard for decision- making where a person has impaired capacity. The PPPR Act refers to decisions being made in a person’s “welfare and best interests”, and, under Right 7(4) of the HDC Code, decisions can be made in a person’s “best interests.” However, best interests is not a primary principle of either piece of legislation and there is no guidance on how these best interests decisions are to be made in light of a person’s “will, preferences and rights” under the United Nations Conventions on the Rights of Persons with Disabilities (CRPD).639

  5. How best interests is assessed under the MCA, and the case law around it, is considered below. Recommendations are then made for revised legislation to provide a best interests standard in New Zealand based on s 4 of the MCA.

633 See Appendix C and Mental Capacity Act, s 4. Section 1(5) states that “an act done, or decision made, under this Act for or on behalf of a person who lacks capacity must be done, or made, in his best interests”.

634 Buchanan and Brock, above n 34 at 3.

635 See Chapter 2 Supported decision-making.

636 Wye Valley NHS Trust v Mr B, above n 171.

637 Donnelly, above n 254 at 176.

638 Donnelly, above n 254 at 177.

639 Article 12(4) of the CRPD uses the formulation ‘rights, will and preferences’.

  © 2020 Alison Douglass