[ADMB Users] sdreport

[Mollie Brooks]

Hi,
I'm looking for information on how sdreport vectors are calculated.

I'm doing a multivariate normal model and I use the solve function to calculate my objective function from the predictions and the variance-covariance matrix. 

I'm interested in the uncertainty of my predictions. So I put them into an sdreport vector. I've looked at CIs calculated as (prediction +/- 2*std) and they are way too narrow (almost never include the true value). I'm wondering if I should try calculating the standard deviations from scratch or if ADMB does exactly what I would do with the variance-covariance matrix. The other possibility is that my measurement error only model is bad and I need to include process error.

thanks,
Mollie

Mollie Brooks
Ph.D. Candidate
NSF IGERT Fellow
Biology Department
University of Florida
mbrooks at ufl.edu
http://people.biology.ufl.edu/mbrooks