With the cell validation feature you can set up your cells to only accept certain values, even from the beginning of data collection. Much like a validated field in REDCap, this prevents any terms other than those on the list from being entered as data values. For this example we'll work with the Other Diagnosis column in the NEISS small subset spreadsheet.
Custom lists are used to make sort orders appear in Excel in a specified way. For instance, if you had a column where the data values were the spelled-out months of the year and sorted it, the order would be alphabetical (April, August, etc.) rather than the order in which the months occur in the year. Here we'll demonstrate how to apply a custom list while also doing more data wrangling on the Months column from the Splitting Multi-Valued Cells exercise. If you completed that exercise with the NEISS small subset dataset, you should have a column called Month with the months represented by their numbers.