# Projpred multilevel reference model demo error

**URL:** <https://discourse.mc-stan.org/t/projpred-multilevel-reference-model-demo-error/30477>\
**Category:** Modeling\
**Tags:** rstanarm, projpred, brms\
**Created:** [February 20, 2023, 8:25pm UTC](https://discourse.mc-stan.org/t/projpred-multilevel-reference-model-demo-error/30477 "2023-02-20T20:25:23Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Michelle](https://avatars.discourse-cdn.com/v4/letter/m/6de8d8/32.png) [@Michelle](https://discourse.mc-stan.org/u/Michelle)\
**Post date:** [February 20, 2023, 8:25pm UTC](https://discourse.mc-stan.org/t/projpred-multilevel-reference-model-demo-error/30477/1 "2023-02-20T20:25:23Z")

</div>

Hello,

I am trying the multilevel reference model demo in [projpred: Projection predictive feature selection • projpred](https://mc-stan.org/projpred/articles/projpred.html) and got the following error, could you please help me to solve it? Thank you very much.

```plaintext
Error: 'mkNewReTrms' is not an exported object from 'namespace:lme4'
In addition: Warning message:
Some Pareto k diagnostic values are too high. See help('pareto-k-diagnostic') for details.

```

Here is the rstanarm code in the demo

```plaintext
data("VerbAgg", package = "lme4")
refm_fit <- stan_glmer(
  r2 ~ btype + situ + mode + (btype + situ + mode | id),
  family = binomial(),
  data = VerbAgg,
  seed = 82616169, QR = TRUE, refresh = 0
)

```

The same error appeared when using brms

```plaintext
refm_fit <- brm(
  r2 ~ btype + situ + mode + (btype + situ + mode | id),
  family = bernoulli(link = "logit"),
  data = VerbAgg
)

```

---

<div class="post-metadata">

**Author:** ![fweber144](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.mc-stan.org/fweber144/32/15592_2.png) [@fweber144](https://discourse.mc-stan.org/u/fweber144)\
**Post date:** [February 21, 2023, 8:09am UTC](https://discourse.mc-stan.org/t/projpred-multilevel-reference-model-demo-error/30477/2 "2023-02-21T08:09:41Z")

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Perhaps you don’t have the most recent (CRAN) version of lme4 installed? If that is the case, I will consider adding a specific version requirement for lme4 within projpred.

---

<div class="post-metadata">

**Author:** ![Michelle](https://avatars.discourse-cdn.com/v4/letter/m/6de8d8/32.png) [@Michelle](https://discourse.mc-stan.org/u/Michelle)\
**Post date:** [March 6, 2023, 2:41pm UTC](https://discourse.mc-stan.org/t/projpred-multilevel-reference-model-demo-error/30477/3 "2023-03-06T14:41:05Z")

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Hi @fweber144 sorry for the late reply. Updating lme4 worked in my case. Thank you very much.