Where do inaccuracies in contact databases come from? Is it a point-of-entry validation problem? A lack of list management policies? Understanding the types of events that lead to data inconsistencies is a vital step in overcoming errors and setting up a system for alerting employees when they do occur, David Loshin says in an article for the Data Roundtable.

He notes that there are two kinds of events that can introduce an error to the system, the first being the change in a record's value. If there isn't an effort to verify the change, such as a customer's birth date, on the part of the customer service representative, an inaccuracy can arise. This is less of a concern if the client is making the change.

Customers who move create another opportunity for mistakes to pop up, Loshin explains.

Sometimes an event takes place (i.e. a consumer moves) and there is a lag time before the outdated address is flagged and verified in the system. He gives the example of a bank sending out an annual privacy policy in June and a customer moving in January. For a time, the inconsistency doesn't matter, but the bank should undergo a periodic address validation project to update its records before sending out the next round of mail.