I want to exclude rows from an SSRS report based upon a field value and display a message if, as a result of filtering, there are no results
I'm a little confused on your logic, because the visibility expression =IIF(Count(Fields!ALERT_VALUE.Value,&quot;DataSet1&quot;)=0,False,True) will  hide the row if the count is 0 which is opposite the logic it sounds like you're trying to achieve with =IIF(Count(Fields!ALERT_VALUE.Value,&quot;DataSet1&quot;)=0,&quot;No Commitment Warnings&quot;, nothing) and based on what you said. If so, then all you may need to do is flip False and True around in your visibility expression like this =IIF(Count(Fields!ALERT_VALUE.Value,&quot;DataSet1&quot;)=0,True,False).
For reference, SSRS's functions are derived from VBA, so you can find the docs on the IIF Function here.