diff --git a/NAMESPACE b/NAMESPACE
index 1c5fe66c..3b477fab 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -82,11 +82,13 @@ importFrom(mmrm,VarCorr)
 importFrom(rstan,extract)
 importFrom(rstan,sampling)
 importFrom(rstan,summary)
+importFrom(stats,aggregate)
 importFrom(stats,as.formula)
 importFrom(stats,binomial)
 importFrom(stats,coef)
 importFrom(stats,df.residual)
 importFrom(stats,lm)
+importFrom(stats,model.frame)
 importFrom(stats,model.matrix)
 importFrom(stats,pnorm)
 importFrom(stats,pt)
@@ -100,6 +102,7 @@ importFrom(stats,sd)
 importFrom(stats,setNames)
 importFrom(stats,terms)
 importFrom(stats,uniroot)
+importFrom(stats,update)
 importFrom(stats,var)
 importFrom(stats,vcov)
 importFrom(utils,capture.output)
diff --git a/R/lsmeans.R b/R/lsmeans.R
index 4cc57f4d..092c7c84 100644
--- a/R/lsmeans.R
+++ b/R/lsmeans.R
@@ -163,6 +163,7 @@ collapse_values.default <- function(x) {
 #' @param data A data.frame
 #' @param frm Formula used to fit the original model
 #' @param fix A named list of variables with fixed values
+#' @importFrom stats update model.frame aggregate
 #' @name ls_design
 ls_design_equal <- function(data, frm, fix) {
     assert_that(