hi Stacey,
when you're dealing with a selection formula that is only using AND, then brackets are not an issue. the issues are usually caused by NULL values interupting the selection formula.
here's what you may wish to do:
1) do a Save As with the report you have
2) in the new report, copy your record selection filter and then comment out the entire record selection
3) create a new formula and paste in the filter syntax that you copied
4) put this formula in the details section
now you have a TRUE or FALSE on all of your records representing whether or not that record will be returned or not...i.e. a TRUE represents what would normally be returned with your filter.
now find a record where you believe that is should be a TRUE but is actually a FALSE...these are the records where your filter is failing. at this point, go into your formula and then comment out the last line...
{Hospital_Privileges.Ending_Date} >= currentdate and
{?Department}={Hospital_Privileges.Department} and
{Hospital_Privileges.Professional_Staff_Category} in ["ACTIVE", "ASSOCIATE", "MOD-ACTIVE", "TERM"] and
{Hospital_Privileges.Hospital_Position_Number} <> ""
//and isnull({Hospital_Secretary_Info.Ending_Date})
now run this...does it make a difference? next uncomment the 2nd last line
{Hospital_Privileges.Ending_Date} >= currentdate and
{?Department}={Hospital_Privileges.Department} and
{Hospital_Privileges.Professional_Staff_Category} in ["ACTIVE", "ASSOCIATE", "MOD-ACTIVE", "TERM"]
//and {Hospital_Privileges.Hospital_Position_Number} <> ""
//and isnull({Hospital_Secretary_Info.Ending_Date})
hopefully this process will help you find out where it is failing as you'll be able to compare against all records.
-jamie