Here’s the thing. If you want to measure how much cash is in your pocket, you count it. Right?
If you count 48 pence, then you have 48 pence. You don’t have 47 pence. You don’t have 49 pence.
Agreed?
If you count how much is in your pocket every hour or so and write it down, you have an amazingly accurate yet highly uninteresting record of the highs and lows of the cash in your pocket.
If loads of different people all around the country all do the same as you, then you end up with a fascinating collection of data all about the change in everybody’s pocket.
I’m sure somebody with a degree would find that a fascinating collection to examine, prod, dissect and discuss for a year’s worth of funding.
But, one thing that would be sure is that the record of cash in pockets wouldn’t and couldn’t change. It is a finite collection of data. Ok, there may have been times when the person making the record had mistakenly counted a fifty pence piece as a ten pence piece. Years later, if this was discovered, then obviously a record would need to be adjusted.
Realistically though, how often is this likely to happen? And how often is an adjustment going to be needed across a whole number of cash in pocket records? And how many adjustments?
So, if I proudly presented my historical record of cash in my pocket, would I be bemused to see that after 15 years, the record changed at the hands of somebody else. And a year or two later it changed again. Then again a year or two after that.
If I was to query why, I’d be told that the count I’d made needed to be ‘homogenised’, and that a back projection from a computer model of all my cash in pocket counts said that the revised count was now what was true.
So, my count of 48 pence in my pocket on July 1st 1998 was no longer valid. The record was to be adjusted down to show I had 47 pence. A couple of years later it got adjusted down again to 46 pence.
The fact is that I had 48 pence in my pocket on that day. However, the record has been changed to suggest I only had 46 pence.
That would be bonkers, right?
So, how come it is not bonkers when the Met Office does this exact same thing with historical temperature records? Every few years they are being adjusted down to present a far colder past than was actually recorded.
No. You’re right. It is bonkers.
England's England 