Koolau
Give me a museum and I'll fill it. (Picasso) Give me a forum ...
My truck has a gauge that tells me my mpg at any given moment. It's like a stopped clock in relation to the number it shows when I switch it over to "average fuel economy." Other owners of a similar truck on a forum I frequent tell me the "average" number is optimistic.
I just went for my annual "wellness" checkup. I weighed myself at home that morning and, lo and behold, the scale at the doc's office said I was 3 lbs heavier than my home scale. Which scale is wrong? Maybe the doc wants to scare me into healthy living, or the bathroom scale folks just want to make me happy with their product.
Those are micro measurements compared to the macro scale of the US economy. If a pickup truck or a bathroom scale can't get measurements right, how much accuracy can you expect from a relatively small crew of statisticians dealing with millions, billions and trillions?
The world is full of uncertainty, people. We're more comfortable with "the truth, the light, and the way." But that's not the way the world works. Margin of error doesn't equal conspiracy.
I suppose in all such situations (mpg to weight on scales) it's good to see who benefits from "higher numbers" (or lower, as the case may be.) By the way, I've careful checked my mileage on both cars and one car reads 8% high every time and one car reads 4% high every time. Not huge errors, but folks who don't confirm the numbers might think their car is really great on mileage when it's exaggerated high. Could happen with any number where it can make "something" look better or worse. YMMV