Which statement about the parallel change method is true?

Which statement about the parallel change method is true?

• A. the new system is available immediately
• B. the outputs from the old and new system can be compared to check that the new system is working correctly
• C. parts of the new system are implemented one at a time to allow users to get used to that one particular process
• D. the old system is kept online to test the new system

Answer: (B)

Running both systems in parallel means the old and new systems operate at the same time for a period. This lets you compare their outputs to confirm the new system is producing the same results and behaves correctly before retiring the old one. It’s chosen when accuracy matters and you want to catch data conversion errors or logic mismatches early. The other ideas describe different changeover methods: an immediate switch-over, a phased rollout, or keeping the old system online mainly for testing rather than producing live, verifiable output from both systems at once. Hence, the statement that outputs from the old and new system can be compared to check that the new system is working correctly is true.

Running both systems in parallel means the old and new systems operate at the same time for a period. This lets you compare their outputs to confirm the new system is producing the same results and behaves correctly before retiring the old one. It’s chosen when accuracy matters and you want to catch data conversion errors or logic mismatches early. The other ideas describe different changeover methods: an immediate switch-over, a phased rollout, or keeping the old system online mainly for testing rather than producing live, verifiable output from both systems at once. Hence, the statement that outputs from the old and new system can be compared to check that the new system is working correctly is true.