One and a half times less

Sounds like nonsense to me. I have no idea what they might mean, I'm sure there are far, far better ways of describing whatever they intended to say.
'Professional' does seem to cover a multitude of sins - I had a pupil offer to clean my car recently 'a professional valet service'. I asked what made it professional? They were charging for it 😂

Think I heard the same thing - NFU  woman on Countryfile? It just felt like she chucked the number in at the end of the interview to sound impressive whilst avoiding any deeper discussion about what it actually meant.

Clearly a professional idiot.

So let’s say “normal” is 100. What would you assume 1.5x Lower means?

to me that would indicate -50. A number one and a half times lower than 100. I’m an utter dimwit when it comes to maths though despite trying hard to improve.

Professional just means they get paid for doing something. There are literally millions of shite professionals in the world.

That one is obviously one of the top.

Yep, heard that too on Countryfile.  Percentages, fractions and statistics and their correct presentation have an enduring ability to bamboozle even the brightest of minds.

My brother used to work in reprographics and an architect client brought in large format drawing that he wanted ‘reduced by 300%’

Yeah I think it probably was Coutryfile, it happened to be on when I turned on the TV and it was about greenhouse gas emissions from different farming methods.  The number couldn’t be negative.  It’s bad enough if the speaker uses crap language (I dare say if you point a camera at me I might misspeak), but the presenter and producer both heard that and thought nothing of it - which surely means they weren’t listening or interested in what she was saying.

If the thing is 1, then 1x less is zero. 1.5 less must be -.5

Like someone telling you an option is twice as dangerous. That sounds terrible. But if the original risk is 1 in a million, it's doubled to 2 in a million. Not really significantly different.

It's nonsense.

How about 'twice as slow' or 'twice as small' instead ot half the speed or half the height.

Weirdly enough, to my mind 1.5 times less would mean divide by 1.5. However, describing it as two thirds of the amount would be much clearer

Sounds like nonsense to me.

... is what I was about to say.

Honestly, it's a folly to waste time unpicking other people's bollocks. Ask for clarification or chuck it in the F*** It Bucket.

If the thing is 1, then 1x less is zero. 1.5 less must be -.5

well that would be logical if it could be a negative number… but this couldn’t be (well I suppose technically it could have been but that would have been so sensational it would have been very explicitly stated).

10x less potent would mean potency of 0.1 times original. 1.5 times less denotes original/1.5.

Dammit how are we going to refute that now and not look like idiots?

Like someone telling you an option is twice as dangerous. That sounds terrible. But if the original risk is 1 in a million, it’s doubled to 2 in a million. Not really significantly substantively different.

FTFY. "Significantly" is used to mean "statistically significant", which just means that it's unlikely to have occurred by chance. A change from a 1 in a million occurrence to a 2 in a million occurrence can be statistically significant if you have a large enough data set, even though it's not a substantive change in your odds of dying.

Whether it is statistical significance or some other type of significance depends on context. Unless you know your audience are statistics savvy, you need to use "statstically significant",

Percentages, fractions and statistics and their correct presentation have an enduring ability to bamboozle even the brightest of minds.

Well, they certainly do mine! I’m pretty sure I have Dyscalculia. I can’t ever work out how to do simple percentages with a calculator! 😖

Dyscalculia
Dyscalculia is a disability resulting in difficulty learning or comprehending arithmetic, such as difficulty in understanding numbers, learning how to manipulate numbers, performing mathematical calculations, and learning facts in mathematics. It is sometimes colloquially referred to as "math dyslexia", though this analogy is misleading as they are distinct syndromes. Dyscalculia is associated with dysfunction in the region around the intraparietal sulcus and potentially also the frontal lobe. Dyscalculia does not reflect a general deficit in cognitive abilities or difficulties with time, measurement, and spatial reasoning.

Like someone telling you an option is twice as dangerous. That sounds terrible. But if the original risk is 1 in a million, it’s doubled to 2 in a million.

It’s funny how 2 in a million sounds a lot less likely than 1 in 500,000 even though they are the same.

half as much as 3 times less?

Well its a bit messy but I can see how you'd end up using it to describe probability of something happening,, i.e. it's this but if such happens it's one and quarter more likely and if the other , one and a half times less.

And that describes a skewed distribution better than 1 1/4 more or 2/3 less.

10x less potent would mean potency of 0.1 times original. 1.5 times less denotes original/1.5.

1x less then means what? The same as 0x less! No sorry 0x less would just explode into infinity. 100% less.

I'm 100% less than impressed with this. 1x less would be nothing less! Who came up with this?