What is de‑duplication and why is it so important? Mr Jones recently received a mailer forwarded to him from the Royal Mail. It was from his building society, and contained an address he had vacated...

What is de‑duplication and why is it so important?

Mr Jones recently received a mailer forwarded to him from the Royal Mail. It was from his

building society, and contained an address he had vacated over two years previously. He

complained to the company and was told it was a ‘computer error’. Explain how the building

society could have avoided this problem.