Data validation is the process of checking database to ensure that the information gathered from different data sources is clean, accurate and in a standard format. Data validation can be simple or complex, depending upon the way it is performed. For example, validating email address, or phone numbers is easy. On the other hand, checking different data fields for consistency and accuracy in a master database will be complex. In a nutshell, data needs to be validated at the same stage/level where it’s most likely to be erroneous.