need help with formula syntax

I'm trying to use the Formula Editor in PRD to add conditional logic to a display property. Specifically, I want to check of a multi value list parameter contains a particular value. If the value exists, set the property to 'true', else 'false'.

I tried the following formula. But it doesn't work. I suspect there's just something wrong with the syntax:

=IF(IN([param];"value");"True";"False")

Any ideas? Also, is there a good reference document for formula expressions in PRD?

Thx,
RR