In Advanced Collections, what is the difference between Strategy Work Items, Tasks, and Interactions

 I am implementing Advanced Collections in R12 using strategies.  I have strategy work items that are associated with my strategies, but I do not have any tasks that are being automatically assigned.  Are tasks generally associated with dunning plans?  If not, how are tasks assigned when using strategies?

Another question...when completing manual work items, is there any way to track the outcome of the work item?  For instance, if one of my manual work items is a collections call, does the collector click "Complete Work" after he made the call, even if the call was unanswered?  Where would the collector record any attempts made with regard to the specific work item?