Three weeks later, that figure comes back up
The supplier invoice arrives by email on Wednesday morning, the person who records purchases opens it, looks at the taxable amount, retypes it into the business software, and after a two-second lapse writes twelve hundred where it said one thousand and twenty, then saves, closes the PDF, and moves on to the next one
For three weeks nothing happens, the wrong figure sleeps inside the business software and looks like any other figure, nobody has a reason to look at it twice
Then the month-end reconciliation comes round, the books are out by an amount nobody can trace, and the hunt begins, the entries get reopened, the PDF gets downloaded again, everything is compared line by line, and in the end it turns up, it was that one
Finding it is the point where you catch your breath, and it's exactly the point where the work starts
The cost isn't the error, it's the chain it sets off
You have to phone the supplier to work out whether the problem is yours or theirs, and the call doesn't last two minutes because on the other end they have to go looking too, then the entry has to be put right, and if the payment has already gone out with the wrong amount you need a credit note, or a reversal, or one more line to explain to the accountant
The reconciliation has to be done again, the supplier balance has to be checked again, and since one error found plants a doubt, a spot check on the rest starts up as well, which is the time of a person who was supposed to be doing something else
The real bill for one figure entered wrong is the sum of all that, and there's no line in the accounts with that name, you pay it in hours
Every manual step is a place where you can slip
A data entry error doesn't depend on how good the person doing it is, it depends on how many points you have lined up between the document and the field in the business software
If the number has to be read from a PDF, held in mind for two seconds, retyped into a field, and then copied again into a second program because the two don't talk to each other, you have set up four chances where there could have been one, and it doesn't take a bad day, a colleague walking in to ask you something while you're copying is enough
A machine gets things wrong in another way
An automation gets things wrong in a different way, and that way can be governed, a system that reads the document and fills in the fields doesn't get distracted, at line four hundred it does the same thing it did at the first, and it's never in a hurry because it's Friday evening
The biggest difference though is another one, a person in doubt takes a guess now and then because there's a pile of invoices to get through, an automation built the way it should be doesn't try to guess, if the line total doesn't come to the document total it stops, if the supplier isn't in the records it stops, and the case ends up in a list a person looks at calmly the next morning
There's the other side too, an automation that gets something wrong doesn't get it wrong once, it gets it wrong the same way on every case until you notice, which is why the checks around it count more than the reading, and why you start out running alongside a person
Where the nets go
The defenses you need aren't complicated, they're the same ones a careful person with infinite time would carry out, and that's exactly why by hand they almost never get done
- the totals that have to match the sum of the lines, the most solid net there is on an accounting document
- the data that has to exist before it gets written, the supplier in the records, the VAT number in a valid form, a date that makes sense
- a threshold beyond which the case doesn't go through on its own, because a number out of scale is almost always an error
- a log of what was done and when, which lets you reconstruct things without going from memory
If you're interested in how these nets are built there's a guide of its own on how you stop an automation doing damage
How to look at your own case
To work out whether any of this applies to you, no analysis is needed, take the last data entry errors that cost you half a day, and count what they set in motion, who made a phone call, what had to be done again, how long afterwards you found them
That time, multiplied by the number of times it happens in a year, is the item we're talking about, and on the work out the savings page you can set it beside the time data entry takes away from you, the other half of the sum
Muffin Suite works on the points where the data moves from a sheet to a screen without anyone having to think about it, because those are the points where you slip, and the odd case stays with the person who knows how to judge it