Formula help to match multi select values

@Michael McS

I would recommend using IF with OR and HAS functions.:

=IF(OR(HAS(Drivers@row, "Washington"), HAS(Drivers@row, "Idaho"), HAS(Deliveries@row, "Washington"), HAS(Deliveries@row, "Idaho")), "West", "No")

Comparing multi-select values to a lookup column is a more complex task.

Editing after a quick test - not so complex after all. Call your helper column "WestStates":

=IF(OR(HAS(WestStates:WestStates, Drivers@row), HAS(WestStates:WestStates, Deliveries@row)), "West", "No")

Yes, those should work as well.

I prefer to use HAS when working with multi-select columns, just because it's more precise. There's a lot of confusion with regards to HAS and CONTAINS, so much so that I re-wrote part of the HAS function help page to make it more clear. (Previously, the HAS page was just a hastily copied version of the CONTAINS page.)

• The HAS function is designed to work with multi-select dropdown and multi-contact columns. It won’t cause an error if used with other column types, but it will only return true if the criterion exactly matches the contents of the cell or a distinct value within a multi-select or multi-contact cell.
• Sample usage: =IF(HAS([Day of Week]: [Day of Week], "Monday"), "yes", “no”)
• In the example above, if [Day of Week]1 is in a Text/Number column, HAS will return “true” if [Day of Week]1 = “Monday” but will return “false” if [Day of Week]1 = “Monday Tuesday.” If [Day of Week]1 is in a multi-select column, HAS will return “true” if [Day of Week]1 = “Monday” and will also return true if [Day of Week]1 contains values of “Monday” and “Tuesday”. It will return “false” if the value in [Day of Week]1 = “Monday Tuesday”. 
• The HAS function is distinct from CONTAINS because it searches for specific values where CONTAINS searches for strings or characters containing the criteria.
• For example, using HAS to search for “apples” will only return true if “apples” is by itself in a text/number column or is a distinct value within a multi-select column. Using CONTAINS to search for “apples”, on the other hand, will return true if it finds “apples” in any part of a text/number cell, or within any distinct value inside a multi-select cell.