When to Seek a Testamentary Capacity Evaluation for Your Client
By Dr. Tyler Gerdin, PsyD, ABPP | Gerdin Psychological Services
Your client is 86. She’s sharp, funny, and tells a good story. She also brought her new neighbor to the meeting, the same neighbor who now drives her to the bank, and she wants to leave him the house her three children grew up in.
You’ve done this long enough to know how that file might look in five years.
Most estate attorneys have a good instinct for when something feels off. The harder question is what to do with that instinct. A well timed capacity evaluation is one answer, not the only one, and not a magic one, but often the strongest record you can build while your client is still here to speak for herself.
The Banks v Goodfellow Test and Its Four Requirements
In Banks v. Goodfellow (1870), an English court weighed the will of John Banks. Banks had serious mental illness. He believed he was being persecuted by a man who had long since died.
The court upheld his will anyway. His delusions had nothing to do with his property or his family. In explaining why, Chief Justice Cockburn laid out four things a person making a will must be able to do.
Understand the act: know they are making a will and what it does.
Know their property: a general sense of what they own, not every account balance.
Know who has a natural claim: the family members and others who would expect to be included.
Be free of a disordered mind that bends the plan: no mental disorder or delusion may “poison” their feelings toward others or warp their sense of right.
One point clinicians and courts both stress: this is a test of understanding, not memory (Burns et al., 2024). A client who can’t recite her account numbers may still grasp, clearly, what she owns and who it’s going to.
How Washington State Testamentary Capacity Law Lines Up
Washington has its own body of case law, but it closely parallels Banks.
The first three parts live in the “sound mind” requirement of RCW 11.12.010. Washington courts read that phrase to mean the testator understands the transaction, comprehends generally the nature and extent of their property, and recollects the natural objects of their bounty (In re Estate of Schafer, 1941; In re Estate of Moulton, 1970).
The fourth part lives in Washington’s insane delusion cases, and here’s a detail worth getting right: a qualifying delusion is treated as a failure of capacity, not a separate claim. The court in In re Estate of Gwinn (1950) described the capacity question as having two aspects: general unsoundness of mind, and partial insanity from a specific delusion. The leading case, In re Klein’s Estate (1947), defined a delusion as a false belief from which the person “cannot be dissuaded by any evidence or argument.” There, an 81 year old widow cut out her only daughter based on an unfounded belief the daughter had tried to poison her. The will was set aside.
Three guardrails keep the doctrine narrow.
The delusion has to change the will. The Klein court asked, in effect, whether the heir would likely have received more but for the delusion. In In re O’Neil’s Estate (1949), a will survived alleged delusions about the testator’s daughters because they didn’t drive his choices. In Gwinn, a will fell because a father disinherited his son over accusations the son never made.
Bad reasoning isn’t a delusion. A belief reached by reasoning from evidence, however flawed, doesn’t qualify (In re Meagher’s Estate, 1962). A testator may also make an unjust, unreasonable, even cruel will; strong dislike of a relative isn’t enough on its own (Gwinn).
The law starts on your client’s side. A will that is rational on its face and properly executed is presumed valid. After probate, the contestant carries the burden (RCW 11.24.030) and must prove invalidity by clear, cogent, and convincing evidence (Meagher).
Why Capacity Is Only Half of What You Need to Document
A client can have full capacity and still sign a will that fails for undue influence (Dean v. Jordan, 1938). You know the Dean v. Jordan pattern: a confidential or fiduciary relationship, a beneficiary who actively helps procure the will, and an unusually or unnaturally large share going to that beneficiary. Together with other circumstances, those facts can raise a presumption the proponent must rebut.
I can’t tell a court whether undue influence happened, that’s a legal finding. What a capacity evaluation can do is document clinical vulnerability (cognitive decline, dependence, isolation) and capture your client explaining her plan in her own words, alone, with no beneficiary in the room. That record matters on both questions.
Red Flags That Signal a Capacity Evaluation Is Worth Pursuing
The research on contested wills points to a consistent set of warning signs. In a Canadian study of will challenges, 72% involved a radical change from a prior will, 56% involved allegations of undue influence, and 40% of testators had dementia (Shulman et al., 2005). A referral is worth serious thought when you see:
A dementia or cognitive impairment diagnosis. It doesn’t defeat capacity, but it nearly guarantees the question will be asked.
A sharp break from earlier wills, especially one that cuts out a child or favors someone new.
Beliefs about family that don’t add up. If a belief rests on real (even flawed) reasoning, Washington won’t call it a delusion. A record made at the time still helps sort out which it is.
The Dean v. Jordan pattern: a helper who is close, involved, and set to receive an outsized share. Isolation and dependence are well known clinical warning signs (Peisah et al., 2009).
Serious or terminal illness. Delirium (a sudden, shifting state of confusion) is common in hospital and end of life care, and easy to miss in a short visit (Liptzin et al., 2010; Peisah et al., 2013).
Why Timing Is the Most Important Factor in Any Capacity Evaluation
English courts offer the so called “golden rule”: when an older or seriously ill person makes a will, a medical professional should examine them and record the findings (Kenward v. Adams, 1975). It isn’t Washington law, but the logic travels well. An international expert panel reached a similar view: an evaluation done at the time of signing can strongly shape how a later challenge turns out (Shulman et al., 2009).
The alternative is a retrospective review built on thin records and witnesses who already disagree. That’s also where “lucid interval” arguments tend to show up. Washington has long recognized that a person with mental illness may have lucid intervals (In re Lundgren’s Estate, 1936), though some researchers argue the idea fits dementia poorly (Shulman et al., 2015). Either way, a documented evaluation near the day of signing beats an argument about good days and bad days.
The bottom line: an evaluation on the front end costs far less than litigation on the back end.
What a Capacity Evaluation Cannot Do
You’ll get more from an evaluation if you know what it can’t do.
It’s evidence, not a verdict. The court decides capacity, and any expert’s method, timing, and scope can be challenged.
It isn’t risk free. If testing shows real impairment, that record now exists. The ABA has flagged the ethical questions a “prophylactic” evaluation can raise for counsel (ABA Senior Lawyers Division, 2025). Talk through possible outcomes with your client, and with me, before the referral, not after.
It works best alongside your file. Your notes, the attesting witnesses, and your client’s own words carry weight. A good report should fit with that evidence and explain it.
It informs your judgment; it doesn’t replace it. RPC 1.14 already guides how you represent a client whose capacity may be diminished. An evaluation just gives you better information for that call.
How to Refer a Client for a Capacity Evaluation in Spokane
My evaluations are built around the four Banks questions and the Washington standards that grew from them.
A call with you to clarify the referral question and the signing timeline.
A clinical interview, with your client alone, about the will, their property, their family, and the reasons behind their plan.
Standardized cognitive testing of memory, attention, language, and executive function (planning and reasoning).
A careful look at beliefs about family members, what the client believes, what it rests on, and whether it explains the plan.
Record review and, when appropriate, input from others who know your client.
A plain language written report organized around each element, delivered in time for signing.
The approach draws on the joint American Bar Association and American Psychological Association handbook on assessing older adults (Wood & Moye, 2008).
One line I never blur: I describe what your client understands and believes, and why. Whether that meets the legal standard is for you, and, if it comes to that, the court.
If a client fits one of these profiles, or a file just keeps nagging at you, I’d welcome a call. I’m Dr. Tyler Gerdin, a board certified clinical psychologist (ABPP) in Spokane. I also complete independent medical and forensic evaluations, so I know what it means to write a report someone else will pick apart.
Call 509-676-4313 or email drgerdin@gerdinpsych.com to discuss a referral.
Frequently Asked Questions
What is the Banks v. Goodfellow test?
The four part standard for making a valid will, from an 1870 English case. The person must understand what a will does, know their property, know who has a natural claim, and be free of any mental disorder or delusion that distorts their plan.
Does Washington follow Banks v. Goodfellow?
Washington has its own case law test, and it closely parallels Banks. The “sound mind” standard covers the first three parts. The insane delusion cases, which treat a qualifying delusion as a failure of capacity, cover the fourth.
Can a person with dementia or mental illness still make a valid will?
Yes, it’s possible. John Banks himself had delusions, and his will stood. What matters is whether the person can do this task at this moment, and whether any delusion actually shaped the will.
Will a capacity evaluation defeat an undue influence claim?
Not by itself. Undue influence is a separate legal question. An evaluation can document vulnerability and your client’s own reasons, but it can’t rule undue influence out.
What if the results show impairment?
That’s a conversation to have before the referral. I’m glad to walk through possible outcomes with you in advance, so there are no surprises.
When should the evaluation happen?
As close to signing as practical, ideally within days. The closer the timing, the stronger the record.
Do you accept referrals from outside Spokane?
Yes. I work with attorneys throughout Spokane, broader Washington, and the Inland Northwest.
Dr. Tyler Gerdin, PsyD, ABPP is a board certified clinical psychologist in Spokane, Washington, specializing in forensic psychological evaluation, neuropsychological assessment, and independent medical examinations.
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