Doram If the seller weighs1,000 bags and finds they have a 10 gram variation, they should make sure every bag has 10g more, so that every buyer gets at least the advertised weight (and no buyer should accept getting 10g less).
I get what you’re saying, but even that would not achieve what you want. It’s in how averages (or rather, arithmetic meas) work. If they weigh 1000 bags, some individual bags could be out by much more than that, and ohrs much less.
Even if you mean do 1000 individual weighings, each of which is out by <10g, so they add 10g, it will only tell them that they’ve achieved your goal for that specific 1000 bags, not that it will be true for the next 1000.
And at what cost? There’ll be a lot of extra equipment, and/or labour time, to do it so the cost of every bag goes up. Which we pay for.
The point of the legisation is about, essential, two things - making sure tha the customer gets a “fair” deal, and making sure that the manufacturer can’t (legally) rig the system. It isn’t about accuracy, but sufficient accuracy. Is 10g under accurate enough? On a 250g bag, no. But on the load on a 40-tonne truck? Or the cargo capacity of a 747, or a container ship? it’s all relative. In other words, materiality.
Also, don’t forget that what this is all about is simply whether the actual weight exceeds advertised weight. That does not reference, in any way, the cost of the beans. If we were to insist manufacturers ALWAYS exceed stated weight, that in itself is dead easy to do. Just stick 50% (or 100%, or whatever) more beans in. If a 250g bag actually weighs 375g, or 500g, they’ll be over the stipulated weight. But all that will happen is the ost per g of beans goes up by 50%, or 100% r whatever. It satisfies the articial requirement of every bag hitting the stipulated weight, but achieves nothing for the consumer.
Materiality is central. How many consumers do you think care about tiny variances in the weight of a bag, so small that it doesn’t matter to them, and when that variance can be both under or over. You might get 249g instead of 250g this time, but the previous bag equally might have been 251g instead of 250g. Result is, over time, we all get a fair deal while any individual bag might be a tiny bit over or under.
In all those words I used, which was a lot yeah, I mentioned Maximum Permissible Error (MPE). That is the amount by which a given scale can be out (compared to those verified weights) and still be accurate enough. And even on a given retail-grade scale, like in shops or supermarkets, how much that is depends on what part of the reading range of the scale you’re looking at. In terms of g, it’s much lower at, say, 100g than it is at 5Kg or 15Kg. The logic is obvious - when buying (say) 10g of saffron, a 1g variation really matters but when buying 5Kg of spuds, nobody (sensible) cares if it might be 4999.5g, or 50050.5g. Materiality.
I calibrated thousands of those scales rior to supermarket installation. Very, very rarely, as in maybe 1 or 2 in those thousands, did they give perfect (accurate) calibration results. But they either worked suffiiently accurately (within MPE) or they didn’t get installed. Even then, having them calibrated in a test centre doesn’t mean they’re still accurate once installed in-branch, not least due to getting bounced around in trucks on the way to the branch. So they get checked again, once in-situ. And either recalibrated to within MPE if they fail, or replaced if they can’t be. By that time, they’re close enough to not matter. At that moment. But even that doesn’t ensure they’re still that accurate the next day, or next month.
Most commercial scales, though, have sufficient build quality and logic that they just don’t go a long way out of range yet still give a stable reading. If they’re really out of kilter, they typically won’t give a stable reading at all. And, most supermarkets have a test weight, usually 1Kg or 2Kg for those 10Kg+ or 15Kg+ scale and do their own quick test regularly - start or zero the scale, stick a test weight on it and see if you get the correct or close reading on the scale. If you don’t, do they user checks, like a quick clean (which often solves problems) and retest, and if that doesn’t resolve it, well, that’s why they have maintenance contracts. Close that checkout and call an engineer.
It’s all about ensuing the consumer doesn’t get an unfair deal, systemically, though an occasional tiny error (either over or under) is unavoidable. Or rather, unavoidable without significant extra cost, which consumers will end up paying for.
As I said, I agree with you in principle. It’s sheer practiality tht causes the problem, where the fix is likey to end up costig the consumer much more than the problem it fixed.
If you regularly get significantly less than advertised weight in, in our case, coffee, I’d suggest a complaint to the supplier. Any reputable ones will immediately check their scales. Disreputable ones might be trying to rip people off, and no amount of scale manufacturing quality or testig procedures will stop that. One method - zero the scales, stick a 5g weight on them then the product you’re weighing, and even putting 250g in according to the scale is only going to result in 245g going in. So, do we install CCTV covering every scale, and then spend a fortune having independent regulatrs reviewing the video? Of course not - it’ll cost a fortune. So if you keep getting under-weight product, the seller probaby has a scale problem, which they should address. If it still carries on, complain to Trading Standards, who do (with a pattern of such complaints) do both random tests.inspections, and secret purchases. Oh, and change where you buy.
In princciple, I agree with you. In practice, it isn’t …. well, practical … to be absolute about it.
