Barcodes exist to eliminate the errors and time it takes to key data into a terminal. But applying and maintaining barcodes can also be expensive and time consuming.

Studies have shown that an average error rate of 3% can occur with keyed data entry. By scanning a barcode, this error rate can be reduced to under 0.03%!

In situations where barcodes are impractical or too expensive, the accuracy of keyed data can be greatly increased by adding one or two extra "check digits" to the slot or product number to be entered.

The chance that ten information digits plus two check digits will be entered in error, but be accepted as valid is 0.07%, almost as good as a barcode. Of course keying in 12 digits will take some time, so the saving from not bar-coding must be balanced against the keying labor.

In cases where only 3 or 4 characters (plus one or two check digits) is required, keying of digits is probably quite practical, especially if product is not already bar coded during manufacture (Most retail items are made with pre-printed UPC barcode labels.)

Bar-coding articles:
Barcode Secrets.
Barcodes for Business.

Barcodes = accurate data entry