AF helps you determine how accurately each field predicts the specified field. As an example, look at the following data:
02/03/2011 01:00,st=CA,state_no=1,vote_no=1
02/03/2011 14:00,st=CA,state_no=1,vote_no=1
02/03/2011 01:00,st=MA,state_no=2,vote_no=2
02/03/2011 02:00,st=MA,state_no=2,vote_no=2
02/03/2011 07:00,st=MO,state_no=4,vote_no=1
02/03/2011 08:00,st=MO,state_no=4,vote_no=1
If you run the following search:
* | af classfield=vote_no
You can see that there is a 100% chance (1.0) that my state (state_no) will predict my vote (vote_num), by looking at the accuracy field (acc). You can also see that state is always declared for a vote (cocur = 1).
The use case here is to determine if we can use the data to predict which state will vote for which candidate and with what accuracy we might make a prediction. This is too small a dataset to make accurate predictions, but given a much more representative dataset, I could, with reasonable confidence, predict that a CA or MO voter will pick candidate #1.
HTH
ron
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