I've just been bitten by a value list issue and found a solution that may prove useful to some folks. This is pretty elementary. The issue is between two value lists. Let's call them "Yes/No" and "Yes/Blank". Logically there's no reason to use "Yes/No" since Table::field="No" in this case is the same as Table::field <> "Yes". So . . . no difference really. However, when using the Count function, and looking for the number of "Yes" values in a given field, a found set of 8 records with either "Yes" or "No" will return 8. Using the Yes/Blank method, if 1 record has the "Yes" value and all others are Blank, Count will return 1 . . . the desired result.
I find myself occasionally dealing with "legacy" (bad) code because I started writing this solution several years ago and had no idea, at the time, of future implications of my coding, or of anything else really.
I've learned a lot reading and asking on this Forum.