Data validation doesn't happen by accident; it requires a thoughtful approach. The more proactive you are about integrating it into your marketing processes, the fewer headaches you'll face down the ...

Excel’s data validation feature is underused because many users don’t realize how versatile it is, especially where dates are concerned. Dates seem to complicate things, but only in your head!

We’ll use data validation to prevent duplicate numbers in the Membership Number column. First, enter the following function into cell K3: =COUNTIF(Table1[Membership Number],B3) ...

Under the Data Tools group, click on the Data Validation option. Check the Data Validation value under the Settings tab. If the values entered there are incorrect, edit them and click OK.

Validation is an automatic computer check to ensure that the data entered is sensible and reasonable. It does not check the accuracy of data. For example, a secondary school student is likely to ...