Psi-conditional

[goodwins]

Could someone explain this part of the output?

DERIVED parameter - Psi-conditional : [Pr(occ | detection history)]

From the way it’s written, it looks like it’s the probability a site is occupied, given the detection history. Is that accurate? How is this computed, and how does it relate to overall estimates of occupancy? I can’t seem to find any documentation.

Thanks!

[jhines]

You're right, it's the prob. of occupancy, given detection history. So, for sites where there was at least one detection, PSI-cond = 1. For sites where there were no detections:

PSIc = PSI*Q/(1-PSI + PSI*Q)

where Q = (1-p)^k, k=# surveys

Since we're only looking at sites with no detections, we should expect PSI-c to be equal to or smaller than PSI (which includes sites with detections).

Jim