"Less than" or "fewer than"?

[Melpomene]

Should it be "less than 28 days later" or "fewer than 28 days later"?

In theory "fewer than" is more correct, isn't it? But it doesn't sound quite right.

I think 'fewer than' too. Or 'less than a month later'. I think 'less than' is in such general usage, it starts to sound correct even when it isn't.

Since 'days' is a plural countable noun, I think it should be 'fewer'. Happy to be corrected though!

Less is used with expressions of measurement or time.

Ah, yes, I think chugnut is right!

Fewer, because you can count them and they are specific.

Less refers to things by volume, or in such quantities that are not realistically countable.

So it would be less sand, or fewer grains of sand. Less water, fewer litres of water, a less full basket, or fewer items in the basket. Less money but fewer pounds and pence. Geddit?

Aha, this guidance agrees with Chugnut. (Scroll down to the last few paragraphs.)

But you're talking about one expanse of time, so "less" could be OK, depending on what come before it. It's "less time" not "fewer time", so in the context of the whole sentence, "less" might be better. "28 days or earlier" would keep all pedants happy.

My lovely dad taught me a good way to tell the difference.

You can have less mash potato and fewer chips.

If you can pick up an individual one (ok so you can't pick up a day but you can remove one from the "pile") it is fewer. If taking an amount (a spoonful) away makes the "pile" smaller, it is less.

So, I would say fewer

Or to put it another way:

"Less than a year later" is correct.
"Less than a day later" is correct.
So "Less than 28 days later" is also correct. The "less" qualifies the amount of time, not the number 28. We're not counting days here, we're measuring an expanse of time, just like if your height is 4' 6" or less you can't go on a ride, etc.

Fewer. Absolutely. No room for debate. Say whichever you like, but 'fewer' is correct.

Prism's argument is flawed:
I ate less than a whole apple
I ate fewer than 10 apples.

You cannot extrapolate from 1 to many in this case.

Yes, but in that case you are talking about how many apples you ate, not the amount of apple you ate, because you are only eating whole apples. If it were "flour" you'd say you used less than 10 bags of flour, if you used, say, 9 and a half. In the case of time, if you take less than 28 days to do something, it's just that- "less than 28 days", which makes perfect sense because you are talking about one thing- the amount of time.

There is room for debate, but I'm right.

I'd have said fewer.

Although "fewer' is correct for discrete amounts, I think it sounds a bit odd because of mental overlap with 'in less that twenty eight days' time', in which the time is the thing there is less of, and it is not discrete.

If it is a discrete measurement ie can only take particular values (time to nearest minute, number of apples) then it's fewer. If its continuous (can be measured anywhere on a continuous scale) eg time, height, weight etc then it's less.
However, agree with chugnut re less being used for time and measurement. It sounds more right. However I'm a mathematician so what would I know.
(Unhelpful then)

Crikey...I love that mash / chips way of remembering - thank you!

And your Dad.

Less. It isn't about whether you can count them precisely, but whether you could in context cut them up.

eg Susan has fewer than three children (actually two).
but
The average woman has less than two children (actually 1.8).

That said, sometimes days aren't cut-up-able, eg "Pilots are required to be available for work on no fewer than 185 days per annum."

Other languages helpfully distinguish between day as in calendar date and day as in 24-hour period, one being discrete and the other continuous.

And whether one counts or measures nouns is ultimately cultural. Some cultures count milk; some measure cows.

Chugnut is correct, and prism. It's "less than 28 days later", because you're talking of one period of time which is 28 days long, rather than of 28 separate days. The fewer/less than rule doesn't apply in the same way to lengths of time or distance.
news.bbc.co.uk/1/hi/magazine/7591905.stm

The clue, going back to the OP, is the word "later". This means we are comparing one point in time with another, not counting days. How much later? Less than 28 days. So we are dealing with this:

t < 28

which I'm sure anyone would agree (especially you, MustTidyUpMustTidyUp), means

"t is less than 28"

and t ⊂ R

If it were t ⊂ N and t ⊄ R, we would have a problem.

But it isn't, so it's "Less".

IMHO.

Ah. That didn't work. Set theory symbols don't work on Mumsnet. What an appalling oversight!

prism

Prism you are right. I was wrong. You have a fine mind and your explanations have made me change! Not often that happens.

yep agree with chugnut cos apparently time and money are uncountable - which is odd as we spend a lot of time counting them. but there ya go.

Burberry
"Tiny Tim has less than ten pounds in his bank account."
"Scrooge has fewer than ten pound coins in his pocket."

yes exactly but only if they were coins right?