Check this out

There has been a revolution in supermarket checkouts over the past 12 months or so. Supermarkets are demonstrating a hitherto unprecedented level of trust in their customers by allowing them to check out their own shopping. This saves on wages and potentially saves the customer time. There is a risk that some customers will take advantage of this idea by not checking items out, or by committing card fraud - however, these risks can be mitigated against to some degree with random checking, and any rise in theft must have been shown to be less than the benefits to the supermarkets.

There are a few systems in place right now:

Scan at checkout

Seen in Tesco, B&Q

The idea here is that the customer shops as usual, and then proceeds to an automated checkout where they scan each item. Once scanned, the item is placed into a 'bagging area' where a scale checks the weight of the item matches what was scanned. As bags become full they can be removed.


No special training is needed. A voice gives instruction. The customer can decide to use the system after shopping.


Some items don't scan well - and there isn't an obvious way to type in the number from scratch. Some light items do not register as being placed in the bagging area. Once the system has been used a few times, it is easy to 'run ahead' of the system and scan faster than it can cope with. The insistence that every item is placed in the bagging area adds delay. There is no obvious way to tell the system 'here is one pot of yoghurt, I have 5 more just like it'.


I will use these systems, but for more than a few items I find they're more trouble than they're worth. I find the voice nagging and slow. It'd be better if I could scan my clubcard at the start and it'd remember my preferences 'expert user, no voice' - these could be adjusted online.

Handheld Scanner

Seen in Sainsbury

The idea here is that as the customer shops as usual, they scan the barcodes of the items. At checkout, there is a 'fast' lane, where the customer's scanner is checked. Occasionally a random 'rescan' is done (I am guessing that the probability of a rescan goes up if previous scans were in error - and that some level of error will cause them to revoke the fast-track rights). The 'Electric Death' site suggests two errors lead to always rescanning. This seems too absolute to me, as wait long enough and virtually everyone would have two errors. There would have to be some 'aging' to this, i.e. an old error is 'worth less' than a new - and correct rescans improve the customer's rating (with new rescans counting for more than old). I'd like to know how this has evolved since the system was introduced.


A very fast checkout most of the time, and a running tally of the shopping bill.


Not every item is 'in the system', so occasionally there are 'problem items'. I assume this is because the scanner doesn't connect to the main database each time. These items must be kept separately and rescanned at checkout. Most of the time, if I get a problem item it'll remain on the shelf.

Why not record the barcode of the 'problem item' on the scanner and pass this to the checkout for checking on the main database?

The scanner does not adjust for offers in the running total. These are corrected for at checkout. Also, at checkout, the system has sometimes allowed a tagged item to go home without the tag being removed - this is a pain.

Some customer training is needed to use the scanner.


I like this system a lot - it operates as fast as the user and drastically reduces time at the end of the shop when you just want to 'get out of there'. The rescan is a pain when it happens, but seems intelligent (i.e. to reduce in frequency with accurate rescans). They will sometimes not have a 'fast track' lane open, but what's really nice is that if you approach the checkout with a scanner, and there are queues then they'll rush to open a 'scanner only' lane for you.

The big problem is that so far I've only seen it in Sainsburys. Also, the system is not connected between stores - if I register for the system at Store A, and go into Store B then I need to register there as well. This is rather daft in this day and age - the stores should be able to communicate this information.

Universal Problem

One big problem with all checkouts in the UK is the Chip and Pin device. This is usually mounted in an easy to see location, so the customer can't miss it. Unfortunately they were not designed in such a way that when the pin is entered, the keypad is obscured. Thus one can stand and read pin numbers as people type them - a recipe for muggers.(*) Why weren't they designed with a deeper 'shield' -so that if you needed to look you had to remove the hand - but with the hand in, the keypad couldn't be seen?

Ah well, as things stand right now - I'll shield my pin, and the mugger skimming numbers will focus on the easier targets all around me. An ex-colleague had his pin cloned by an oik who had the cctv trained on the card reader, they got the card number by freeze-framing the card as it went in, and the pin by watching the fingers - if the handheld is detachable, detach it to avoid this issue!

(*) I once decided to be helpful to a friendly-looking lady in a queue by saying that she should hide her pin for this reason, that she entered it in a way that the number could be read (I knew it by standing behind her). I got back 'if I get mugged in a minute I'll know who to blame then!'... yeah, muggers forewarn their victims! And they wonder why people aren't helpful any more?

Tesco Language

Tesco is to change the wording of signs on its fast-track checkouts to avoid any linguistic dispute.

The supermarket giant is to replace its current "10 items or less" notices with signs saying "Up to 10 items".

Tesco's move follows uncertainty over whether the current notices should use "fewer" instead of "less".


Whilst '10 items or fewer' is more linguistically correct than '10 items or less', 'up to 10 items' does not just 'clarify' the meaning (who was unclear?) it actually changes the meaning.

'10 items or fewer/less' implies the number of items can be 10. 'Up to 10 items' implies that anything from 1 to 9 is okay, but 10 is too many.

With the change, it's possible that jobsworths on the till might have a resurgence. I hope not! I haven't had one of those in some time.

All this is just fussing round the edges - appealing to the grammar pedants. I'd much prefer it if Tesco could sort out its pricing policy, that'd be a useful change.


I found myself in Tesco the other day, doing a shop. I also found myself getting really annoyed.


It was the pricing policy. With a range of items, it can be hard to compare prices, so they 'helpfully' put on the shelf label something like 57p/100g.

Some may object to the SI system being used there. I don't, in fact, I think it's a crying shame that we're stuck halfway between the imperial system with its funny numbers of subunits and the SI system.... but that isn't an argument I want to get into here, it's a distraction from the main point.

Tesco Mustard Pricing

What I objected to was the lack of consistency of which units were chosen for the shelf label - not between different types of item, but between different types of the same class of item. I won't always go for the cheapest item - but if I am paying more it's helpful to be able to fairly compare how much more I'm paying!

Mustard, for example, had prices per kg, prices per 100g (okay, annoying but not too tricky) and prices per 100 millilitre... what? To make a direct conversion I would have to carry around the density of that brand of mustard in my head. I could make an educated guess of about 1gram/millilitre (i.e. asume it's mostly water) - but that could easily be 10% out, making the final price per 100g roughly 10% out - rendering it pointless.

I didn't really care what the basic unit was for price comparison, only that it was the same unit. By mixing units like this the labels are obscuring the information that they're trying to make clear.

I thought that what's happened is they've got some bit of software doing this which says 'If it's over X pence per 100g, give the price as pound sterling per kg' and the same bit of software chooses whether volume of mass is the appropriate unit (kg is a unit of mass, not weight, there is a difference - imperial doesn't make the distinction). Why on earth can't they make their pricing software say 'It's mustard. Look at the results of the other mustard calculations, and if the majority are prices per 100g, then we'll force that for all mustard and flag up any lines where the mass is unknown for referral to the supplier'.

Actually, it's not even that - as some of the pricier mustards are per kg. What is going on?

It is not an excuse to say 'some jars are labelled in millilitres, and some in grams therefore it's all we can do'. Tesco have enough clout to be able to say to their suppliers 'give us this data if you want us to stock your product' - and this certainly wouldn't explain the 100g vs kg inconsistency (which is annoying but not insurmountable by the customer).

The only reasons I can think of for the status quo and for this bit of logic being missing are:

  1. Genuine oversight.
  2. Deliberate obfuscation, whilst trying to appear helpful (i.e. making more expensive products as price per 100g or price per 10g, whilst making cheaper products price per kg)
  3. Incompetence.

Whichever is the truth, the lack of consistency within product lines got really annoying, and I decided to fill out a comment form. At the front of the store was the 'customer feedback' display board, which contained the usual selected quotes asking for things they'd implemented years ago, with the smug 'reply' underneath. No forms were to be seen...

I went to 'customer service' for a form, waited to be served, and then had to wait for them to hunt for a form for me. I didn't get the impression that they got asked for these often. Hint to Tesco: If you really want customer feedback, make the forms really obvious - don't hide them away.

I've requested a reply. Let's see what they say. I hope they sort it out; every little improvement would help...!

As an aside: Interestingly, the kilogram is the only base unit with 'kilo' in front of its name. I wonder how that happened?

Supermarket 2.0

Via Userfriendly I came across an excellent video on glumbert parodying 'Web 2.0' (for those not in the know, that's all the sites that have tagging, rss feeds etc) What if a supermarket went 2.0? I particularly liked the reference to 'Ajax', to 'Stumbleupon', and the ever-present tagging.

I loved the delicious punning, and the cookie.

I think my favourite part was the flickr reference with quakr.