Testamentary capacity is the cognitive capacity of the testator to make or alter a will.

Many people now pass away in their late 80’s or 90’s with dementia. If they made a will after age 70 it may be open to challenge on the basis that the dementia may have been present and having an impact, even if undiagnosed, at the time of drafting and execution.

The NSW Supreme Court has pointed out that the best way to safeguard the will, and the firm who prepared it, is to have an independent contemporaneous assessment of testamentary capacity at time of execution.

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In the leading case of Banks v Goodfellow (1870) LR 5 QB 549, Cockburn CJ said (at 565):

“It is essential to the exercise of such a power that a testator shall understand the nature of the act and its effects; shall understand the extent of the property of which he is disposing; shall be able to comprehend and appreciate the claims to which he ought to give effect; and that no disorder of the mind shall poison his affections, pervert his sense of right, or prevent the exercise of his natural faculties—that no insane delusion shall influence his will in disposing of his property and bring about a disposal of it which, if the mind had been sound, would not have been made.”

In Ryan v Dalton (31 July 2017) Justice Kunc provided a “postscript” on “questions of capacity” “proposing some basic rules of thumb” as “basic precautions” for solicitors to take to protect their clients, and themselves, particularly in relation to


  1. over 70;
  2. being cared for by someone;
  3. who resides in a nursing home or similar facility; or
  4. about whom for any other reason the solicitor might have concern about capacity.”

His Honour noted that:

“the effort involved in paying attention to questions of capacity at the time instructions for a will are taken and the will is executed (including, where necessary, obtaining an assessment of the client where it is thought one is called for) pales into insignificance with the expense, delay and anxiety caused by litigation after the testator’s death”.

Given the risks to the testator’s intentions and to the solicitors involved in drafting a will it is now accepted good practice to obtain an independent contemporaneous assessment of cognitive capacity at the date of the execution of the will if any of the above criteria exist.

The expert will usually be someone specialising in mental faculties such as a psychologist, neuropsychologist, psychiatrist or a geriatrician. Other experts may be required if a specific medical condition is the cause of the cognitive problem.

The question of whether a (more expensive) specialist clinical psychologist is required or whether the assessment can be appropriately completed by a registered psychologist, as well as the nature of the interview and examination required and the nature and extent of testing required, will depend upon the circumstances of the particular testator and will.

While the legal tests for different transactions are different, and depend upon the person understanding the nature and effect of a the particular transaction, the underlying expertise issues are the same whether assessing mental capacity or cognitive capacity for testamentary capacity, capacity to execute a power of attorney, appoint an enduring guardian, to commence or continue litigation, to plead guilty, marry or give a gift. See related pages for other specific transaction types.

Sample Reports

For some fields of expertise we have some sample sections of de-identified reports. Please contact our office if you are interested in a sample.


The overall cost of expert opinion depends on the services required. Some of the key factors that affect the cost of advice include:

  • The need for a view or inspection of a location
  • The quantity of documentary material to be reviewed
  • Whether there are reports of other experts to be reviewed and commented on in detail
  • Whether there is a need for conferences with the expert either in person or by telephone/Skype
Relevant Cases Ryan v Dalton; Estate of Ryan [2017] NSWSC 1007 (31 July 2017)

"Rules of thumb" include testing those: "over 70, being cared for, in a nursing home, about whom for any other reason the solicitor might have concern about capacity.

Guthrie v Spence [2009] NSWCA 369

No single test of capacity. Different thresholds for marriage, powers of attorney, litigation and wills. The issue is the capacity to understand the nature of the transaction when it is explained. (Citing Gibbons v Wriight (1954) 91 CLR 423 at 437)

Szozda v Szozda [2010] NSWSC 804

Power of attorney. Key issues for person to understand.

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    Profiles of Experts in Legal capacity - testamentary capacity

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