How to use Bound

I put
Bound(Surprise%Q1, -100, 999)
in a screen and it does not filter anything except companies with 0.0.

Hello. The Bound function is not a filter. It will change any value that falls outside the range you specified to the min or max you specified. Use the rules below in a screen to see what it does:

showvar(@boundSurprise, Bound(Surprise%Q1, -100, 999))
showvar(@Surprise%Q1, Surprise%Q1)

For example, GPS:USA has a Surprise of 138,843. Your Bound rule would return 999.