The Excel IF () function returns “Duplicate,” when the Excel function, COUNTIF () finds more than one occurrence of the concatenated values in column H. Figure F Image: Susan Harkins/TechRepublic.

Prevent duplicates before they happen by combining a simple function with data validation. Excel has built-in tools to expose and even delete duplicates, but they work on existing data after the fact.

How to Use Excel to Show Only Duplicate Values. Business issues such as incorrect transactions, data entry errors, technical glitches and poor system design may cause duplicate values in your data ...