Boyce index interpretation

[Uyên Bùi]

Dear fellows,

I am at the end of my analysis of the model performances assessed by the Boyce index metric, AUC, and TSS. While the laters have a wide-spread interpretation for their value, I seem to be unable to find a paper with clear instructions on how to interpret the Boyce index score. I would appreciate it if you could help me by providing either papers with instructions or your personal interpretation (with a back-up explanation). 

I hope this will not take much of your time to help. Thank you in advance.

Best regards,

Uyen.

[Rogério]

Hi Uyen,

Look at the enmSdmX function evalCountBoyce:

Details

CBI is the Spearman rank correlation coefficient between the proportion of sites in each prediction class and the expected proportion of predictions in each prediction class based on the proportion of the landscape that is in that class. The index ranges from -1 to 1. Values >0 indicate the model's output is positively correlated with the true probability of presence. Values <0 indicate it is negatively correlated with the true probability of presence.

References

Boyce, M.S., Vernier, P.R., Nielsen, S.E., and Schmiegelow, F.K.A. 2002. Evaluating resource selection functions. Ecological Modeling 157:281-300. doi:10.1016/S0304-3800(02)00200-4

Hirzel, A.H., Le Lay, G., Helfer, V., Randon, C., and Guisan, A. 2006. Evaluating the ability of habitat suitability models to predict species presences. Ecological Modeling 199:142-152. doi:10.1016/j.ecolmodel.2006.05.017