by Paul Cutler | Mar 28, 2025 | Uncategorized
The so‑called ‘prosecutor’s fallacy’ describes the risk that the fact finding tribunal will reason that evidence of the match probability or the likelihood ratio expresses the probability that an incriminating DNA sample was the DNA of the accused (Wark v WA [2023] WASCA 66). If you want a more succinct definition (from Xie v R [2021] NSWCCA 1) it’s “a fallacious mode of reasoning that transposes the conditional in a likelihood ratio“.
Lies and statistics
Why am I writing about this? Like many ideas for this blog over the years, I came across a case about the prosecutor’s fallacy (which I hadn’t ever heard of) when I was researching something else. I am having flashbacks to studying second year statistics in the early 1980’s when I actually knew something about Baye’s Theorem. In case you’re wondering, Baye’s Theorem is a means of refining probability calculations when more information comes to hand.
Prosecutor’s fallacy – examples
Statistics aside, the best way to describe the prosecutor’s fallacy is with a few examples. In R v Galli [2001] NSWCCA 504, the answer to the question: “What was the probability of the accused having the … DNA of the father compared to a person taken at random?” was 2.4 million to one.
However, the question for the jury was: “What was the probability of the accused being the father?”. Speigleman CJ noted that:
84 One means of committing the Prosecutor’s Fallacy is a reasoning process which treats the answer to the first question as if it was an answer to the second question, i.e. that the probability that he was the father was 2.4 million to one. That is not a permissible form of reasoning.
85 Given the size of the male population in Australia, on the basis of a probability of 2.4 million to one, there would be three or four males in Australia who share the DNA profile of the father of the foetus. A statement in the form that the “odds are 2.4 million to 1 that the accused is the offender” or that the “odds are 1 in 2.4 million that the accused is innocent”, overlooks the number of people who could have committed the offence.
Another example from the English case of R v Adams where the treatment of the evidence was that ‘[o]nly one person in a million will have a DNA profile which matches that of the crime stain” as demonstrating that “there is a million to one probability that the defendant left the crime stain and is guilty of the crime‘. His Lordship observed that the fallacious nature of that statement becomes clear when it is appreciated that the statement that one person in a million has the DNA profile which matches that obtained from the crime scene means that the suspect will be 1 of perhaps 26 men in the United Kingdom who share that characteristic (presumably assuming a population of 52 million with an equal division in gender). Hence, based on those figures alone, the odds of its being the accused are not a million to one. The prosecutor’s fallacy has a defence counterpart which ignores the statistical significance of the other evidence connecting the accused to the crime.
In case you are still awake and want to follow this further you could have a look at: An introduction to statistical ‘evidence’ — (2003) 23 Aust Bar Rev 239.
The image was generated using the AI tool DALL-E
by Paul Cutler | Jan 30, 2025 | Uncategorized
Character cancellation of permanent residence visas is a topic that I have blogged about before. Attempting to get character cancellation decisions revoked in the ART is one of my areas of practice. Usually the odds are stacked against success. In my matter this week the Minister’s lawyers actually conceded the factors were “finely balanced” (fingers crossed).
The ART proceedings are generally conducted politely and professionally and without some of the heat which is often present in commercial litigation. I was very surprised to find a matter where the member unleashed against the lawyers. This is how the decision in Leo’o Olo and Minister for Immigration [2024] AATA 2774 started:
- A non-citizen who commits serious offences in Australia should expect to be removed. Mr Leo’o Olo is a non-citizen who inflicted grievous bodily harm on a stranger, hit his young son so hard it caused welts and bruising, and threw his ex-partner down with such force that she bounced into a wall. He should not expect to remain in Australia. [So far, so good – difficult to cavil with that]
- However, there is money to be made from non-citizens who are desperate to avoid deportation, and whose loved ones are prepared to contribute their savings to pay a lawyer or migration agent to take their case to the Tribunal. There is much less money, but a good measure of integrity, in competently assessing a non-citizen’s prospects of overturning a visa cancellation, and where their prospects are futile, advising them to keep their money. Where a non-citizen’s prospects are not futile, a lawyer or migration agent who takes their case should present an honest case that focusses on matters that favour the non-citizen and carefully deals with matters that do not. Witnesses should be proofed properly to elicit relevant information and drive home their duty to be truthful. Poor proofing leads to contrived or deficient evidence and creates a risk that information that favours the non-citizen will remain unknown unless a curious Tribunal uncovers it. [There is no reasonable prospects of success requirement and no costs orders in this jurisdiction]
- Mr Leo’o Olo did not benefit from the efforts of his lawyers and lay witnesses to manipulate the Tribunal. The Tribunal is concerned with credible evidence and reasonable inferences. It is not persuaded by lies, speculation or exaggeration. Mr Leo’o Olo is going back to his country of origin. It is not a country that is poor, unstable, war torn, barbaric or oppressive. It is New Zealand. [Manipulating the Tribunal is a big call]
I half expected there to be a judicial review bias case subsequently. If there is one there is no decision published yet. I am also thinking about representation generally and representation without fear or favour to the best of your ability? Although I am poking fun at this decision, I hope the underlying conduct of the lawyers didn’t deserve this criticism. Of course I have one last barb….reasonable minds may differ on NZ.
Creative commons acknowledgment for the photograph.
by | Dec 20, 2024 | Uncategorized
Workplace Christmas parties can cause lots of legal issues. In Collins v Signature Blend Pty Ltd t/as Alira [2015] NSWWCCPD 22 there was an issue about when the employer’s liability for workplace injuries ceased (i.e. when did the party end).
The basic facts were that:
- Mr Collins, was the manager, sole director and employee of Signature Blend Pty Ltd t/as Alira, a restaurant in Sydney;
- On 19 December 2011, he and other members of staff attended a Christmas lunch at a restaurant called the Grasshopper at Temperance (oxymoron?) Lane in Sydney. Lunch started at around midday and there was no issue that Mr Collins was in the course of employment while he was at lunch. Signature Blend paid the cost of lunch;
- While at the restaurant, Mr Collins consumed alcohol and cocaine;
- After the lunch, which finished at about 4.00 pm, Mr Collins and some of the attendees at the lunch returned to his apartment at Darling Point where they consumed further alcohol and cocaine on his balcony;
- There was conflicting evidence about what happened next. However, Mr Collins suffered serious injuries when, at about 5.30 pm, he fell about 24 metres from the eighth floor balcony
- Did Mr Collins: (a) do an “irish jig type movement”, lose his grip and fall over the railing; or (b) did he jump the railing attempting to land on the cement ledge?
- It was put more colourfully by the Arbitrator: on a wet, stormy afternoon, with rain coming over a balcony, causing people to go inside, [Mr Collins] made a conscious decision to fling himself over a balcony more than 25 metres above ground, in a fluid single motion (having been to lunch), with a view to hanging on to a wet, slippery, thin metal railing and landing on a narrow ledge on the other side.
You might think the outcome of this case was obvious (it was), but the challenge to the initial arbitration decision was dealt with quite decisively:
“[Signature Blend] did not induce or encourage [Mr Collins] to engage in the behaviour that resulted in him falling from the balcony, including being intoxicated, under the influence of an illegal drug, and jumping on a wet and slippery balcony.”
It follows that, on any view of how Mr Collins came to fall over the railing, the respondent did not induce or encourage Mr Collins to engage in the activity or activities that brought about his injury and he was not in the course of his employment at the time he fell. For the same reasons, his injury did not arise out of his employment and his claim must fail.
So, there you go!
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by | Nov 28, 2024 | Uncategorized
My curiosity was recently piqued by a 2018 article by Gaegler J called “Truth and justice, and sheep“. It is actually quite a serious article about the inter-relationship of truth and justice. So what have sheep got to do this topic? His Honour uses three sheep stories (he thought about calling them parables) as the basis for his discussion.
The first story is about a prosecution for sheep stealing, colloquially known as ‘sheep-duffing’, tried before a local jury in western Queensland. At the conclusion of the trial, the judge asked the jury the customary question, ‘How do you find the accused?’ The response of the jury, delivered through its foreman, was ‘Not guilty your Honour — provided he gives back the sheep’.
The second story came from an 1887 case in Michigan where a Mr Dunbar alleged that his 34 sheep had become mingled with a larger flock of sheep belonging to a Mr McGill. The trial judge directed the civil jury that the question was whether there was more evidence to show that 34 of the sheep were Dunbars than there was to show that they were not Dunbar’s. The appellate court said that was the wrong question with the correct one being: whether there was sufficient evidence to satisfy the jury that the (34) were Dunbar’s sheep.
The third story was about a partnership dispute between two Greek farmers (who were cousins). One cousin alleged that 227 sheep were a partnership asset and the other denied it. After 19 days of trial, McInerney J delivered a judgment in the following terms:
- On the Plaintiff’s Claim, I am not satisfied to the civil standard of balance of probabilities that the sheep existed. Claim dismissed with costs.
- On the Defendant’s Counterclaim, I am not satisfied to the civil standard of balance of probabilities that the sheep did not exist. Counterclaim dismissed with costs.
His Honour says that these stories show that:
- our concept of justice is reliant on our concept of truth;
- our concept of truth is not absolute but a matter of degree. Truth for us is relative;
- true or untrue is proven or unproven; and
- proven or unproven is ultimately believed or not believed with the requisite degree of intensity.
There is also a very interesting discussion about fact finding and the development of the common law system of justice over the last 8 centuries. We’ve all heard of trial by ordeal but I didn’t know about trial by compurgation (you’ll have to google it or read the paper). Also as a fun fact I was surprised to find out that trial by battle was only abolished by statute in 1819 after the last gauntlet was thrown down the year before.
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by | Sep 30, 2024 | Uncategorized
In August 2013, the applicant was charged with an offence under the Commonwealth Criminal Code of using a carriage service in a manner that reasonable persons would regard as being offensive. The matter was dealt with summarily in the Local Court and she was convicted. She then appealed her conviction in the District Court and the matter ultimately made it to the Court of Appeal (see Morgan v District Court of New South Wales [2017] NSWCA 105 )(see below).
She was clearly not on good terms with the local Byron Bay publican when she wrote the following email (which was the basis for the charge):
Re: Update – Life Ban from Hotel Great Northern, Railway Friendly Bar and “all Mooney Hotels”.
The following information is not a threat, it is an attempt to educate – though I concede that comprehending the lesson requires a greater intelligence than that demonstrated by Hannah and Amber to date. Be grateful that I am the sort of person who always resolves disputes lawfully – others would have arranged for Amber and Hannah to star in a ‘snuff f**k’ movie, put a bullet in Mike’s head, sold [their child] to a brothel in a third world country – leaving Tom and Cath alive to wonder whether or not it is really worth f**king over a person simply because you can. Old Celtic saying – Mooney being an Irish name, I trust the Mooney Clann will comprehend the message: “Never start a War without considering the possibility that, should you loose the War – all men will be killed; all women raped and enslaved; and all children butchered”.
So why did this end up in the Court of Appeal? Her (2 years out of time) application for judicial review of her conviction was successful because she hadn’t consented to the matter being dealt with summarily in the Local Court. This obviously impressed Meagher JA who made the following observation:
[21] The applicant appeared in person, having declined the opportunity to be represented by a solicitor funded by a grant of legal aid. Her stated reason for having done so is that as “a Druid (Celtic Pagan Priest) … being represented by a solicitor in Court is not an option.” According to Strabo, druids were once held in such high regard that they could quell any private or public dispute, including a stand-off between opposing armies: Geographica at 4.4.4. Their jurisdiction was divine and limitless. By contrast, and fortunately for the applicant, the jurisdiction of Australian inferior courts is statutory and limited.
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by | Aug 29, 2024 | Uncategorized
As luck would have it I came across another (not) fair and impartial case in the past few weeks. This time it’s a prejudgment case. I didn’t set out to write related blog posts in pairs, but here we go anyway.
This time, it was in a judge alone criminal trial. Senior Counsel for the accused foreshadowed that he would make an application for a directed verdict of acquittal at the close of the Crown case on the basis that there was no case to answer.The following exchange with the trial judge took place:
Counsel:
Well your Honour there will be an application tomorrow for no case to answer.
Judge:
I see, well that application will be refused. So how long then will the defence case take?
Counsel:
How can your Honour possibly come to that view without having heard one word from either me or Mr Wilkinson?
Judge:
Because I’ve closed the Crown case, and I have just said it.
Counsel:
But you’ve heard not one word of any submission by either of us upon either the law or the fact
Judge:
No, I’m simply telling you the application will be refused. I perceive what’s in the Crown case, I perceive there’s a case to answer.
This case made its way to the High Court (Antoun v The Queen [2006] HCA 2). The sole ground of appeal was that the trial judge had prejudged the matter and conducted himself in such a way that a fair-minded observer might reasonably apprehend that he might not bring an impartial and unprejudiced mind to the question of whether the appellants ought to be convicted.
We know from the judgment of Gleeson CJ that after the exchange set out above that on the following morning the Judge “listened to argument on sufferance, then repeated his decision. As it happens, his decision was right. The submission was without merit. That, however, does not remove the impression created by the course that was followed.”
However, as often happens, it’s Kirby J who nails it:
[27]…. it is certainly true that the trial judge’s remarks were strong and forthright. In some circumstances, that will be a permissible expression to adopt, especially where the trial judge is conducting a trial as the sole judge of fact and law and the parties are legally represented by counsel able to respond with clarity and forthrightness. Judicial indignation at a particular course of action, or proposed action, may on occasion be understandable. Couched appropriately, at the proper time and in due sequence, it may give rise to no reasonable apprehension of bias. For centuries in courts of our tradition, judges have been telling parties and their lawyers, sometimes in quite robust terms, that they consider that a particular submission or course of action is hopeless, a waste of the court’s time or doomed to fail. I would not want to say anything that needlessly mollycoddled candid judicial speech addressed to trained advocates…..
[29]….A line is drawn between forthright and robust indications of a trial judge’s tentative views on a point of importance in a trial and an impermissible indication of prejudgment that has the effect of disqualifying the judge from further conduct of the proceedings. Sometimes, that line will be hard to discern. But, in this case, I agree with the other members of this Court that the trial judge crossed it.
Creative commons acknowledgment for the photograph.
The so‑called ‘prosecutor’s fallacy’ describes the risk that the fact finding tribunal will reason that evidence of the match probability or the likelihood ratio expresses the probability that an incriminating DNA sample was the DNA of the accused (Wark v WA [2023] WASCA 66). If you want a more succinct definition (from Xie v R [2021] NSWCCA 1) it’s “a fallacious mode of reasoning that transposes the conditional in a likelihood ratio“.
