The Lemon Fool

All this talk of the "R number" is really bugging me.

"Mr Newton, what is this G number you've discovered?"
"Mr Einstein, is the C number constant"
Traffic cop...." Excuse me sir, but your V number was above the limit" (v = velocity)
"Happy Birthday. What is your Y number?"

Why can't they just say Reproduction rate"?

BellaHubby wrote:Why can't they just say Reproduction rate"?

Because that would be wrong, perhaps?

Scott.

it has also been called the person to person RE-INFECTION rate which makes sense to me .

Re-infection ? As in infected again?

jackdaww wrote:it has also been called the person to person RE-INFECTION rate which makes sense to me .

It's not a "rate".

Scott.

BellaHubby wrote:Why can't they just say Reproduction rate"?

"R" or "R0" (R zero) is short for "Reproduction Number", rather than rate.

They could use the full term, but once it's understood, it might be deemed a bit clunky for repetitive usage, because then you'd want to specify what the reproduction number was associated with etc.

My personal view is that the usage of R0 or "the R number" has been adopted so as to make the speaker sound as if they have more expertise, i.e. they are familiar with this scientific slang, so obviously they'd be familiar with the science associated with it...

I actually don't care which terminology they adopt, but I do care about how various politicians seem to be able to "follow the science" whilst saying different things from one day to the next, despite the science not appearing to have changed...

VRD

vrdiver wrote:My personal view is that the usage of R0 or "the R number" has been adopted so as to make the speaker sound as if they have more expertise, i.e. they are familiar with this scientific slang, so obviously they'd be familiar with the science associated with it...

VRD

I think you've hit the nail on the head

--kiloran

vrdiver wrote:

BellaHubby wrote:Why can't they just say Reproduction rate"?

"R" or "R0" (R zero) is short for "Reproduction Number", rather than rate.

...

VRD

Why R0 (R zero) - what does the zero mean?

Slightly O/T but our highest fault priority is P0 (P Zero)
Not sure who came up with that - P0 is more important than , for example P2

AleisterCrowley wrote:Why R0 (R zero) - what does the zero mean?

R0 is the Basic Reproduction Number, a theoretical value for a population where everybody can catch the virus (nobody is immune).

This is as opposed to the Effective Reproduction Number RE (R with a subscript E) which relates to the actual current state of the population.

I'm sure Boris could explain why R0 rather than RE is always quoted

See https://en.wikipedia.org/wiki/Basic_reproduction_number

Scott.

As the HIGNFY Twitter feed (https://twitter.com/haveigotnews?) points out, the Prime Minister and his entire government have been battling hard to get the R number down over the last few weeks. That's R for Resignations, of course.

BJ

AleisterCrowley wrote:Re-infection ? As in infected again?

===================

i did say person to person .

but its not a rate , my mistake .

may be its a factor?

or does someone here actually know please ?

jackdaww wrote:

AleisterCrowley wrote:Re-infection ? As in infected again?

===================

i did say person to person .

but its not a rate , my mistake .

may be its a factor?

or does someone here actually know please ?

I'm not an expert, or even an "educated man in the street" when it comes to this stuff, but if you want a serious answer, here's one from the horse's mouth: https://wwwnc.cdc.gov/eid/article/25/1/17-1901_article

The basic reproduction number (R0), pronounced “R naught,” is intended to be an indicator of the contagiousness or transmissibility of infectious and parasitic agents.

The rest of the article then explains much more.

VRD

R0 is only used when the whole population is susceptible (well, -1 of course) & thereby reproduction is at its highest level. As herd immunity develops, reproduction falls.

https://en.wikipedia.org/wiki/Basic_reproduction_number

kiloran wrote:

vrdiver wrote:My personal view is that the usage of R0 or "the R number" has been adopted so as to make the speaker sound as if they have more expertise, i.e. they are familiar with this scientific slang, so obviously they'd be familiar with the science associated with it...

VRD

I think you've hit the nail on the head

--kiloran

For those determined to keep ahead of the "sound as if they have more expertise" curve could I suggest they borrow a few impressive terms from nuclear reactor physics - and refer to sub-critical, critical and super-critical states in the virus growth. And to really impress the natives (or the cabinet members) they could refer to the reactivity which is the departure from criticality.

Edit - nuclear physicists refer to the "multiplication factor" with symbol "k" - don't ask me why!

scotia wrote:Edit - nuclear physicists refer to the "multiplication factor" with symbol "k" - don't ask me why!

Whereas epidemiologists use “K” for the variation in individual contagiousness.
https://www.theguardian.com/world/2020/ ... down-eases

scotia wrote:nuclear physicists refer to the "multiplication factor" with symbol "k" - don't ask me why!

The "KABOOM!!!!" factor?

scotia wrote:Edit - nuclear physicists refer to the "multiplication factor" with symbol "k" - don't ask me why!

Well they could hardly use 'm' - 'm' is for mass - so why not 'k'?

XFool wrote:

scotia wrote:Edit - nuclear physicists refer to the "multiplication factor" with symbol "k" - don't ask me why!

Well they could hardly use 'm' - 'm' is for mass - so why not 'k'?

I appreciate that some shorthand character has to be chosen - but the wave number k = 2Pi/lambda was already frequently used in physics
So far I think vrdiver's explanation wins the day

scotia wrote:

XFool wrote:

scotia wrote:Edit - nuclear physicists refer to the "multiplication factor" with symbol "k" - don't ask me why!

Well they could hardly use 'm' - 'm' is for mass - so why not 'k'?

I appreciate that some shorthand character has to be chosen - but the wave number k = 2Pi/lambda was already frequently used in physics
So far I think vrdiver's explanation wins the day

Doesn't everyone use K for transfer function gain?
- because, well... yeah now I think about it

- sd