# What would you call this "double entry" principle in English?

There is a system for entering the number of the ball that falls out in a lottery game. It consists of two computers operated by two different people. They each have to enter the ball number they see so it is double-checked. What would you call such thing in English? Double-entry? Double-check?

• What does a dictionary say 'double check' means? (I'd suggest 'Collins' sense 2b for the noun.) Aug 19, 2015 at 11:03
• Yeah, "double-check" in common terminology, "redundancy" for a more technical term. Aug 19, 2015 at 11:45
• The term double entry is specific to accountancy and is perhaps best avoided here so as not to create confusion.
– WS2
Aug 19, 2015 at 13:03
• independently verified Aug 19, 2015 at 15:57
• If you're emphasizing that two people must do it for security or safety, consider two-man rule. Aug 19, 2015 at 23:41

I think "double-checked" or "cross-checked" would be more accurate than "redundant" here. If the intention was that the system was still usable even if one of the computers fails altogether, that would be a redundant system, but (I assume) it isn't; the cross-checking that both operators agree on the numbers is a necessary part of the system if we want to detect errors.

"cross-checked" is perhaps more precise; the point is to have two independent sources to check against each other, whereas "double-checked" could be a single source being looked at twice. (Though ultimately there's one source, the actual ball with the number.)

Compare cross-check and double-check.

(The next stage would be to have three operators, and to accept results if two out of three agree. Then the third computer is redundant for error detection, but not for error correction.)

• +1 I think you could make it clearer, though, that you are suggesting "cross-check" as your answer and not (if I understand correctly) "double-check". Aug 19, 2015 at 14:52
• I think either is a plausible answer, depending on what part of the situation is to be emphasised, but neither is perfect. "cross-check" doesn't have to use exactly two checks; "double-check" is (or at least suggests) exactly two checks, but doesn't have to be independent; it may be the same check repeated twice. ("double-entry" is (done properly) both, but only in a specific accounting context.)
– armb
Aug 19, 2015 at 15:57
• Hmmm, I don't think it is a double check, it's only a single check. The value is entered on computer A; the value is also entered on computer B; it is checked that the value from computer A is the same as the value from computer B. Aug 19, 2015 at 16:16
• @AndyT - True. Each operator is probably sort of checking the number they typed is the number on the ball they see, but that's rather implicit, and if it counts arguably means the cross-check is a third check. Though without the comparison somewhere, having the two operators is meaningless, so you couldn't have only their two checks.
– armb
Aug 19, 2015 at 17:08

In engineering, we would call it a redundant system.

redundancy: (1b) (engineering) The inclusion of extra components that are not strictly necessary to functioning, in case of failure in other components

{ODO}

This kind of entry is called Two Pass Verification or Double Data Entry.

Two people key data into a system, and then the differences are displayed at the end for verification.

Two-pass verification, also called double data entry, is a data entry quality control method that was originally employed when data records were entered onto sequential 80-column Hollerith cards with a keypunch. In the first pass through a set of records, the data keystrokes were entered onto each card as the data entry operator typed them. On the second pass through the batch, an operator at a separate machine, called a verifier, entered the same data. The verifier compared the second operator's keystrokes with the contents of the original card. If there were no differences, a verification notch was punched on the right edge of the card.

Although it doesn't describe the situation precisely in and of itself, the word independent (meaning 3) is very important here - the number is entered twice, each entry being independent of the other.

Hence a full description of the system (in as few words as I can make it and still fully describe the system) is:

The number is independently entered twice, with the two entries cross-checked for consistency

I don't think that independent cross-check in and of itself is a clear definition.

• Definition for independent provided by dictionary.reference.com
• Credit to armb for cross-check
• Independent can also connote outside, as in, "independently verified by an outside agency." (Your answer isn't wrong, but it could be considered a little ambiguous.)
– J.R.
Aug 20, 2015 at 1:02

This kind of procedure is based on what is sometimes called the four-eyes principle.

The four eyes principle is a requirement that two individuals approve some action before it can be taken. The four eyes principle is sometimes called the two-man rule or the two-person rule.