I'm trying to conduct a simple slopes analysis for a mixed effects model obtained with `lmer`.

The model is similar to the following:

```
data(Orthodont,package="nlme")
mod <- lme4::lmer(distance ~ age*Sex + (1|Subject), data=Orthodont)

```

When trying to conduct a simple slopes analysis with the function `sim_slopes` in the package `interactions`, I obtain the following error message.

```
interactions::sim_slopes(model=mod, pred=age, modx=Sex)

```

> 
> Error: One of the requested columns does not exist.  
> 
>  Backtrace:  
> 
>  1. interactions::sim\_slopes(model = mod, pred = age, modx = Sex)  
> 
>  5. jtools:::summ.merMod(...)  
> 
>  6. jtools:::create\_table(...)  
> 
>  In addition: Warning message:  
> 
>  Johnson-Neyman intervals are not available for factor moderators. 
> 
> 
> 

**Would any one have any thoughts on what the problem might be?**

Note that it works well with the package `reghelper`, but I need p values for these tests, which `reghelper` does not provide.

```
reghelper::simple_slopes(mod)

```

The output of `sessionInfo()` is:

> 
> R version 3.6.0 (2019-04-26)
>  Platform: x86\_64-pc-linux-gnu (64-bit) Running under: Ubuntu 18.04.2
>  LTS
> 
> 
> Matrix products: default BLAS:  
> 
>  /usr/lib/x86\_64-linux-gnu/blas/libblas.so.3.7.1 LAPACK:
>  /usr/lib/x86\_64-linux-gnu/lapack/liblapack.so.3.7.1
> 
> 
> locale: [1] LC\_CTYPE=en\_CA.UTF-8 LC\_NUMERIC=C  
> 
>  LC\_TIME=en\_CA.UTF-8 [4] LC\_COLLATE=en\_CA.UTF-8  
> 
>  LC\_MONETARY=en\_CA.UTF-8 LC\_MESSAGES=en\_CA.UTF-8 [7]
>  LC\_PAPER=en\_CA.UTF-8 LC\_NAME=C LC\_ADDRESS=C  
> 
>  [10] LC\_TELEPHONE=C LC\_MEASUREMENT=en\_CA.UTF-8
>  LC\_IDENTIFICATION=C 
> 
> 
> attached base packages: [1] stats graphics grDevices utils  
> 
>  datasets methods base 
> 
> 
> loaded via a namespace (and not attached):  
> 
>  [1] Rcpp\_1.0.1 magrittr\_1.5 splines\_3.6.0 MASS\_7.3-51.1  
> 
>  [5] munsell\_0.5.0 colorspace\_1.4-1 lattice\_0.20-38 rlang\_0.3.4  
> 
>  [9] minqa\_1.2.4 plyr\_1.8.4 tools\_3.6.0 grid\_3.6.0  
> 
>  [13] gtable\_0.3.0 nlme\_3.1-140 cli\_1.1.0 assertthat\_0.2.1  
> 
>  [17] digest\_0.6.19 lme4\_1.1-21 lazyeval\_0.2.2 tibble\_2.1.2  
> 
>  [21] crayon\_1.3.4 Matrix\_1.2-17 reghelper\_0.3.4 nloptr\_1.2.1
> 
> 
> [25] ggplot2\_3.1.1 interactions\_1.1.0 jtools\_2.0.1 pander\_0.6.3  
> 
>  [29] compiler\_3.6.0 pillar\_1.4.1 scales\_1.0.0 boot\_1.3-20  
> 
>  [33] pkgconfig\_2.0.2
> 
> 
>