Emission line diagnostic diagrams for AGN in SDSS

The use of emission line diagnostic diagrams, and especially the BPT diagram, to either remove or identify AGN in the local universe studies with SDSS is ubiquitous and essential. As it is the largest 
spectroscopic dataset, it is also used to inform studies at higher redshifts. Yet, significant questions remain about how realible the SDSS BPT diagram is considering that its fibers may capture a lot of 
non-nuclear emission from star formation. Furthermore, there is a question of the completeness of the emission-line method of finding AGN irrespective of the potential star formation contamination. Finally, 
there is a perennial question of whether LINERs are indeed AGN. In this talk I will present some novel approaches to answer these questions and some surprising new results.