Triple State

Ok. Thank you for the suggestion about the triple state video. I watched it, but I think my problem is somewhat different. The user has to choose between active and inactive. There is no, "I don't know." All I'm trying to do is use the iif statement to see all of the records, whether true or false. Is there no way to do that?  I can type "True or False" (without quotes) in the criteria and that gives me all the records, but the iif statement does not. Why is that?

Saying "If x = -1 OR 0" is not correct syntax...it would have to be "If x = -1 OR x = 0".  

If these IIF statements are the criteria for a search query, I would recommend removing the criteria altogether for the case "*All Clients*".  If all records are acceptable, just remove the WHERE condition for that case.  Something like:

"SELECT * FROM tblTableName" & IIF(....[ClientStatus]="Inactive Clients", " WHERE CheckboxField=False", IIF(...[ClientStatus]="Active Clients"," WHERE CheckboxField=True",""))

Take a look at the Search Form 2.0 as well.  That will show you how to write the where statement Jeffrey is talking about.

When I remove the condition for "*All Clients*", no records are returned. At first I thought that the problem was because I was dealing with a checkbox, but I switched from checkbox to Number and later to Short Text. What I found out was that it doesn't seem to matter what the data type is. IIf statements cannot handle a compound condition in the "true" argument-- like "-1 OR 0" or "A" OR "I".

I guess I'm going to try the switch function and see if that makes any difference.

The Switch function hasn't solved my problem. Will keep digging.

Can you share a simple example
What options are on the form and what the data looks like.

Here is just one example of how you could accomplish what you are trying to do.
I used the latest copy of the Blank Template because Richard has added in more customers to play with.

Make a copy the CustomerListF.  I named mine CustomerActiveListF.
Edit the form and add IsActive to the list.
While you are there create an unbound Combo Box.  You can use the wizard for this one.
Choose *I will type in the values I want -> Click Next

In the Column 1 type:
     All
     Current
     Inactive
Next

Choose *Remember the value for later use.
Don't worry about a label name - Delete it any way.
Click Finish.

Bring up the properties for the Combo Box you just made.
All Tab
Give it a good name.  I named mine IsActiveFilterCombo
Set:
Default Value:   ="All"
Limit to List:   Yes
Allow Value List Edits:    No

Event Tab choose After Update ->  Code Builder if you don't have it turned off.

See code below.

Again watch the Search Form 2.0
Really consider the Access Search Seminar