Helping with backtransform (get.real)

[Marina FAVARINI]

Hi everybody,

I'm trying to make predictions on Detection probability and my best model has the variable behavior (p0 ~ b). So when I try the get.real appears an error:

pred.df <- data.frame(session = factor(c(1,2))) 

pred.det <- get.real(model = best_model, type= "det", newdata = pred.df) 

Error in eval(predvars, data, env) : object 'b' not found

Does anyone know how to resolve this error?

Best,

Marina

[Daniel Linden]

Hi Marina, can you send your fitted model object to me?  The get.real function should be able to handle predictions of the behavioral effect without needing to specify.

[Marco Salvatori]

Hi everybody,

I am having exactly the same error when extracting detectability predictions " Error in eval(predvars, data, env) : object 'b' not found ". I see there was no full answer to this question, does anybody know how to solve this problem?

Thanks,

Best

Marco

[Chris Sutherland]

Hi Marco,

Can you send me the fitted object and the code you are using (offline: cs...@st-andrews.ac.uk) and I will see what's going on. Then post a general solution.

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[Marco Salvatori]

Hi all,

Thank to Chris's help I could solve the problem. I was using wrong data types in the "newdata" when extracting detection probability and sigma predictions. 

Sex must be specified as a binary factorial variable with 0 and 1 levels (0 for females and 1 for males).

The behavioral effect b instead must be expressed as a binary numerical (not factorial!) variable with 0 and 1.

Session is numerical. See example below:

# predict p
p_df <- data.frame(
  Session = 1,
  sex = factor(c(0,1,0,1)),
  b = c(0,0,1,1)
)
p_df <- get.real(mymod, type='det', newdata=p_df)

Best,

Marco