Balance of Probabilities

Timothea

When a civil claim is put before a court, the judge has to decide whether the claim is valid "on the balance of probabilities." I've always wondered what this really means. This phrase is sometimes explained as meaning "more likely than not." This seems to be a bit clearer.

I am a statistician, not a lawyer, so it is clear to me that both of these phrases refer to the overall probability that the claimant is more likely to be right on the facts and in law than the defendant. However, judges are lawyers, not statisticians. From the many small claims court reports on this forum and elsewhere, it appears that many judges decide cases by dealing with each fact and each point of law in sequence.

This is how it could happen in a private parking claim. The judge decides, at the place and time in question, that:

1. The defendant's vehicle was parked
2. The equipment (e.g. ANPR, ticket machine) was working correctly
3. The signage was sufficient to make a valid offer
4. The lack of advertising consent for the signage is not relevant
5. The parking terms offered were capable of making a contract
6. The parking terms offered were accepted by the driver
7. The driver breached the parking terms
8. The claimant had authority to manage parking
9. The claimant has authority to pursue the claimant for payment
10. The defendant was the driver or is otherwise liable
11. The claimant followed its ATA's Code of Practice
12. The charge is not a penalty and is not excessive
13. The Consumer Contracts Regulations 2013 do not apply

As a result, the judge finds for the claimant. Fair enough, I hear you say.

However, let's see what happens when we include how certain the judge was with each decision made, expressed as a percentage:

1. The defendant's vehicle was parked (95%)
2. The equipment (ANPR, ticket machine, etc.) was working correctly (85%)
3. The signage was sufficient to make a valid offer (80%)
4. The lack of advertising consent for the signage is not relevant (85%)
5. The parking terms offered were capable of making a contract (100%)
6. The parking terms offered were accepted by the driver (75%)
7. The driver breached the parking terms (85%)
8. The claimant had authority to manage parking (90%)
9. The claimant has authority to pursue the claimant for payment (80%)
10. The defendant was the driver or is otherwise liable (90%)
11. The claimant followed sufficiently its ATA's Code of Practice (65%)
12. The charge is not a penalty and is not excessive (85%)
13. The Consumer Contracts Regulations 2013 do not apply (75%)

So what's the overall probability that the claimant is more likely to be right on the facts and in law than the defendant? The answer in this example is 9.4%. This is because the claimant must be right on every point to succeed whereas the defendant only needs to be right on one point to defeat the claim, and the probability of this is 90.6%.

If you disagree with my probabilities then let's make the certainty of each decision 90% (except those that are already higher). In this case, the probability of defeating the claim is still over 70% "on the balance of probabilities."

Discuss...

System

Have you presented such an argument in court?

Courts are binary - it is or it isn't. So the above list is yes/no and not percentages.

So with the very first one, pics of the car showing the correct VRM with a timestamped photo is not 95%. It's 100% unless evidence is shown to the contrary.

And again with #1 above, this is where the excellent work by the Parking Prankster and the analysis of "pics of the car showing the correct VRM with a timestamped photo" was so good. The whole UKPC scam came tumbling down.

So if you want to defeat a case you have to have contrary evidence at [almost] every stage to switch it to your side from theirs.

Timothea

I agree that the long-established procedure for judges in the civil courts is to decide each point in a binary way, either for the claimant or for the defendant, and not to consider the overall probability that a claim is valid. I am merely pointing out the mathematical absurdity of such a procedure.

One possible way around this, from a defendant's standpoint, is to combine arguments into a smaller number of points, such as "the contract is not enforceable," and to provide multiple reasons to prove the point. Some judges may still decide each reason in a binary fashion, but I think it might help judges to see the bigger picture of how the private parking industry operates.

Castle

Timothea wrote: »

I agree that the long-established procedure for judges in the civil courts is to decide each point in a binary way, either for the claimant or for the defendant, and not to consider the overall probability that a claim is valid. I am merely pointing out the mathematical absurdity of such a procedure.

Of course where we have more than one judge ruling, as in the Supreme Court ruling this week (8-3) on Brexit, you end up with a Balance of probabilities decision.

The_Deep

You must also tale into account the individual circumstance of the motorist. Is the car insured for extra driver, do others drive the car on their own insurances? In my case, my wife does most of the driving, especially around town, and we share the driving on long trips. My son, daughter and son in law occasionally drive the car.


If we were asked to name the driver a month ago we might have difficulty

Guys_Dad

We have just had a Brexit Supreme Court judgement. The same facts were presented to the 11 judges. 8 chose to go one way - 3 the other.

These are the most senior judges in the land, yet they differed in their opinion.

Logic and statistics go out the window when dealing with a court and human prejudices take over.

HO87

Guys_Dad wrote: »

We have just had a Brexit Supreme Court judgement. The same facts were presented to the 11 judges. 8 chose to go one way - 3 the other.

These are the most senior judges in the land, yet they differed in their opinion.

Logic and statistics go out the window when dealing with a court and human prejudices take over.

Setting aside, for the moment, any influence of conspiracy-type theory to the effect that there is a possibility that some of the judges were swayed by the interests of the ruling elite in their decision-making, I disagree.

I suggest that the only prejudice - human or otherwise - that can be imputed is the application of logic to the operation of the law as it was written up in the European Communities Act 1972. At the end of the day the difference between the majority and dissenting views hinged on a logical analysis of the Act. Both interpretations fit that logic. If anything I suggest that the decision highlights the impact of human prejudice (or was it just a lack of foresight?) on legal draughtsmanship or at least how it was done 43 years ago. Don't forget we were just joining the EEC then - the Common Market - not trying to exit a proto-federal state.

Handbags-at-dawn

It's a bit like the tossing a coin thing: each toss gives 50/50 heads or tails - but if it's been heads 9 times in a row, should you take into account the improbability of getting 10 heads in a row?

Not completely on all fours perhaps, but another way of looking at Cumulative probability

HO87

I suggest that the argument advanced by the OP is based on a misunderstanding of how the law operates in that he implies that probability plays a part in the consideration of all the legal factors that make up a case. This is almost certainly not going to apply unless a case was so poorly argued and so poorly defended that a judge was left with no option - not that that would be impossible in parking cases. In truth, were a case to be that badly presented then a judge is likely to summarily dismiss it - given that it is for a claimant to make his case not for the defendant to disprove it.

As was made clear at the outset by Emanresu the law is binary - either something is fulfilled or exceeded (or whatever) or it is not. If a condition is unfulfilled that is it. There is no prize for a good effort - until it comes time to consider costs that is.

It is not simply a case of this being a "long established procedure" it is the way in which legal logic works and has to work.

The OP then includes this paragraph:

One possible way around this, from a defendant's standpoint, is to combine arguments into a smaller number of points, such as "the contract is not enforceable," and to provide multiple reasons to prove the point. Some judges may still decide each reason in a binary fashion, but I think it might help judges to see the bigger picture of how the private parking industry operates.

The way in which this is set out suggests that the OP is unfamiliar with the way in which defence arguments are best formulated - a sentence is rarely enough. A "standard" defence in a parking case may run to anything from 15 to 20 pages and in a recent case I am aware of the discussion just with regard to the signage ran to 18 paragraphs. This, I submit, meets the OP's submission:

One possible way around this, from a defendant's standpoint, is to combine arguments into a smaller number of points, such as "the contract is not enforceable," and to provide multiple reasons to prove the point.

Were it no so unnecessarily long - and fairly boring - I'd happily include the 18 paragraphs above to demonstrate how defence arguments are developed. These are rarely posted here or even on Pepipoo or Legal Beagles because they are so long.

HTH