Using lists to limit data entered into a cell

- Data validation rules help limit the data your users can enter into a cell, but they can be frustrating if the rules aren't clear. One of the clearest ways to require users to enter one of a set of options is to define a list of acceptable values for a cell. This is the start of a worksheet meant to capture room reservation data, and it's based on the Landon Hotel's loyalty program. I will start by creating a validation list for RoomType and then do a similar but slightly different operation for GuestLevel.

So I'll click in cell C2, which is where I want to create my room type list. And then I'll go to the Data tab on the ribbon and click Data Validation. That displays the Data Validation dialog box. I'll click the Allow control's down arrow. And from the selection of rules, I'll click List. Doing so displays the controls that I need to use. I will clear the Ignore blank checkbox because I do want to require data entry in this cell.

And I will leave the In-cell dropdown checkbox selected. That way when the user clicks the cell, they will know that they can click a down arrow and select from the available values. Now I need to identify the source of my data, so I will click the Source box's collapse dialog button and select cells F1 through F4, and I'll click the expand dialog button. Everything looks good, so I can click OK. And you can see that a down arrow has appeared to the right of cell C2.

And if I click it, I get a list of acceptable values. And in this case, I'll just pick the first one, Cambridge. But now let's say that the list that I want to use exists on another worksheet. This can happen if you have a worksheet that contains multiple parts. And if it's not easy to copy that data back to the active worksheet, you can still create your list. So I'll click the GuestLevel cell, that's cell D2. And click Data Validation.

And once again I'll click the Allow button and click List. To select a range on another sheet, I will click the collapse dialog button, click the sheet tab of the sheet that contains the data, in this case, Sheet2, and select the data that I want to use. We have five levels, they are Non-participant, Red, Blue, Green, and Purple. With that selection, I can go back to the Data Validation dialog box, click the expand dialog button, and click OK.

That takes me back to sheet number one, and it has applied the rule to cell D2. I'll click the down arrow, and this is one of our best customers, so I'll click Purple. Data validation lists are powerful tools that can help prevent spelling errors and limit your users' data entry to a list of approved values. Be sure to listen to your users, though, to find out if they need to add or edit items on the list that reflect their needs and the realities of your business.