I need to determine if a DCR node exists, and if so, take action, if not.. well, take a different action.

Here's my code that doesn't seem to work:
<iw_iterate list='event_dcr.events.event[0].appearance.performer' var='performer'>
<iw_if expr='{iw_value name="performer.name"} ne ""'>Artists Include: </iw_if>
<iw_value name='performer.name'/><br>
</iw_iterate>
My current guess is that i'm referring to an empty node incorrectly. Can anyone point me in the right direction?
Thanks!
matt