Scaling prediction file and site cov file independently

[Basavaraj Mulage]

Hi all,  I am bit confused regarding scaling the variables during modeling and while predicting it for all the unsurvyed sites. Im using Unmarked package in R for single season single species models

Background : I have 2 site cov  files , one is surveyed site cov file ( surveyed grids 2027)  used for modeling and other one is all site cov file ( surveyed + unsurveyed grids 3068) used for prediction after finding best model. 

Do I need to scale my prediction site cov file ( 3068 grids with surveyed and unsurvyed )  with the means and SD's of surveyed site cov  OR  is it okay to scale them independently ?

someone suggested me that scaling two files  independently will be problematic since model learns/ calculates  beta coefficient values using site cov file used while modeling  and prediction file will have other sites too ( unsurveyd) which will have different means and SDs and it would confuse the models to predict ?

[Marc Kery]

Dear Mulage,

good you asked, since this is a frequent source of confusion, and error. 

You absolutely have to scale the prediction covs using the means and SDs computed from those that you use to fit the model. When we fit a model, the coefficients that we estimate only have a meaning in the context of the specific scaling that we used for the covariates in that model.

Best regards  --- Marc

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From: unma...@googlegroups.com <unma...@googlegroups.com> on behalf of Basavaraj Mulage <basava...@gmail.com>
Sent: Monday, January 19, 2026 07:06
To: unmarked <unma...@googlegroups.com>
Subject: [unmarked] Scaling prediction file and site cov file independently

 

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