diff --git a/DESCRIPTION b/DESCRIPTION
index 762d23b..d43b6b3 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -40,5 +40,5 @@ Suggests:
     MplusAutomation
 Encoding: UTF-8
 Language: en-US
-RoxygenNote: 7.2.3
+RoxygenNote: 7.3.1
 Config/testthat/edition: 3
diff --git a/R/expand_responses.R b/R/expand_responses.R
index 572da47..db9eee2 100644
--- a/R/expand_responses.R
+++ b/R/expand_responses.R
@@ -23,7 +23,8 @@ expand_responses <- function(responses, scoringMatrix) {
             !duplicated(rownames(scoringMatrix)),
             !is.null(colnames(scoringMatrix)),
             !duplicated(colnames(scoringMatrix)),
-            all(setdiff(unique(unlist(sapply(responses, unique))), NA) %in%
+            "All values occuring in the 'response' argument must match some name of the scoring matrix." =
+              all(setdiff(unique(unlist(sapply(responses, unique))), NA) %in%
                   rownames(scoringMatrix)))
 
   responses <- as.matrix(responses)
diff --git a/R/generate_item_parameters.R b/R/generate_item_parameters.R
index b47884f..5a8fae4 100644
--- a/R/generate_item_parameters.R
+++ b/R/generate_item_parameters.R
@@ -218,7 +218,7 @@ generate_slopes <- function(nItems, scoringMatrix, ..., FUN = identity,
 #' by a set of \emph{intercept} parameters describing relative frequency of
 #' specific categories of the response scale. However, it is convenient to
 #' define model parameters in another parameterisation, in which item
-#' \emph{thresholds} describe {difficulty} of switching between consecutive
+#' \emph{thresholds} describe \emph{difficulty} of switching between consecutive
 #' categories of the response scale, and only then transform these
 #' \emph{thresholds} to \emph{intercepts}. Function follows this approach and:
 #' 1) first generates general \emph{difficulties} of the whole items, then
diff --git a/R/make_item.R b/R/make_item.R
index fee6724..9e83c35 100644
--- a/R/make_item.R
+++ b/R/make_item.R
@@ -11,7 +11,7 @@
 #' traits scoring patterns that will be returned by functions provided with
 #' arguments \code{scoringOnPreviousResponses} or \code{editResponse})
 #' @param intercepts a numeric vector of intercept parameters (must be shorter
-#' of one than number of rows in the \\code{scoringMatrix} or the same length
+#' of one than number of rows in the \code{scoringMatrix} or the same length
 #' but with the first element being 0)
 #' @param mode the way the item should be answered - see
 #' \code{\link{generate_item_responses_sqn}} for "irtree" and
diff --git a/man/generate_intercepts.Rd b/man/generate_intercepts.Rd
index f1014d2..e87f36e 100644
--- a/man/generate_intercepts.Rd
+++ b/man/generate_intercepts.Rd
@@ -74,7 +74,7 @@ Assuming \emph{GPCM} response process test item must be characterized
 by a set of \emph{intercept} parameters describing relative frequency of
 specific categories of the response scale. However, it is convenient to
 define model parameters in another parameterisation, in which item
-\emph{thresholds} describe {difficulty} of switching between consecutive
+\emph{thresholds} describe \emph{difficulty} of switching between consecutive
 categories of the response scale, and only then transform these
 \emph{thresholds} to \emph{intercepts}. Function follows this approach and:
 1) first generates general \emph{difficulties} of the whole items, then
diff --git a/man/make_item.Rd b/man/make_item.Rd
index 5b42617..f8f89a3 100644
--- a/man/make_item.Rd
+++ b/man/make_item.Rd
@@ -26,7 +26,7 @@ traits scoring patterns that will be returned by functions provided with
 arguments \code{scoringOnPreviousResponses} or \code{editResponse})}
 
 \item{intercepts}{a numeric vector of intercept parameters (must be shorter
-of one than number of rows in the \\code{scoringMatrix} or the same length
+of one than number of rows in the \code{scoringMatrix} or the same length
 but with the first element being 0)}
 
 \item{mode}{the way the item should be answered - see