Fixing delta in mulit-state model (conditional binomial parameterization)

[Katie Davis]

Hello,

I originally ran all of my models in RPresence but am moving over to unmarked as there is no option for a parametric bootstrap in RPresence other than for a simple single-season model. I am running single-season multi-state models using the conditional binomial parameterization. 

I'm not finding a clear way to fix values of parameters? Specifically, I need to fix delta for my third survey (or for a specific survey method). My third survey was conducted with eDNA (first two were visual surveys) and therefore cannot distinguish between state 1 (species presence) and state 2 (species presence with breeding). Thus, the need to fix delta to 0 for this survey.

Is there a way to do this in unmarked? If I were to not do it, what could the implications be? In RPresence, before I figured out how to fix it, the probability would be estimted as effectively zero (i.e., 1e10), but it seems statistically un-ideal to estimate a parameter I know to be 0.

Thanks for the help!

Katie

[Marc Kery]

Dear Katie,

as far as I know, there is no way how you can fix a parameter in unmarked (without going into the entrails of the code perhaps).

Best regards  --- Marc

---

From: unma...@googlegroups.com <unma...@googlegroups.com> on behalf of Katie Davis <davi...@gmail.com>
Sent: Tuesday, May 20, 2025 01:23
To: unmarked <unma...@googlegroups.com>
Subject: [unmarked] Fixing delta in mulit-state model (conditional binomial parameterization)

 

--
*** Three hierarchical modeling email lists ***
(1) unmarked (this list): for questions specific to the R package unmarked
(2) SCR: for design and Bayesian or non-bayesian analysis of spatial capture-recapture
(3) HMecology: for everything else, especially material covered in the books by Royle & Dorazio (2008), Kéry & Schaub (2012), Kéry & Royle (2016, 2021) and Schaub & Kéry (2022)
---
You received this message because you are subscribed to the Google Groups "unmarked" group.
To unsubscribe from this group and stop receiving emails from it, send an email to unmarked+u...@googlegroups.com.
To view this discussion visit https://groups.google.com/d/msgid/unmarked/8b34098b-5ebb-4bc7-b908-c96a1460cbdan%40googlegroups.com.