diff --git a/ext/EffectsMixedModelsExt.jl b/ext/EffectsMixedModelsExt.jl
index f811410..5ff2575 100644
--- a/ext/EffectsMixedModelsExt.jl
+++ b/ext/EffectsMixedModelsExt.jl
@@ -19,7 +19,7 @@ function Effects.effects!(reference_grid::DataFrame, model::MixedModel;
     # the existence of an appropriate formula method
     form = formula(model)
     form_typical = typify(reference_grid, form, modelmatrix(model); typical=typical)
-    piv = view(model.feterm.piv, 1:model.feterm.rank)
+    piv = view(model.feterm.piv, 1:(model.feterm.rank))
     X = view(modelcols(form_typical, reference_grid), :, piv)
     eff = X * fixef(model)
     err = sqrt.(diag(X * vcov(model)[piv, piv] * X'))
diff --git a/test/mixedmodels.jl b/test/mixedmodels.jl
index de8c6f5..9c7fd5b 100644
--- a/test/mixedmodels.jl
+++ b/test/mixedmodels.jl
@@ -7,8 +7,8 @@ using Test
 
 rng = StableRNG(42)
 x = rand(rng, 100)
-data = (x = x, x2 = 1.5 .* x, y = rand(rng, [0,1], 100), z = repeat('A':'T', 5))
-model = @suppress fit(MixedModel, @formula(y ~ x + x2 + (1|z)), data; progress=false)
+data = (x=x, x2=1.5 .* x, y=rand(rng, [0, 1], 100), z=repeat('A':'T', 5))
+model = @suppress fit(MixedModel, @formula(y ~ x + x2 + (1 | z)), data; progress=false)
 dropped_idx = model.feterm.piv[end]
 dropped_coef = coefnames(model)[dropped_idx]
 kept_coef = last(fixefnames(model))