diff --git a/.DS_Store b/.DS_Store
index 9bde138..b376042 100644
Binary files a/.DS_Store and b/.DS_Store differ
diff --git a/R/sampledata.R b/R/sampledata.R
new file mode 100644
index 0000000..a6c4851
--- /dev/null
+++ b/R/sampledata.R
@@ -0,0 +1,25 @@
+#' Systematic review sample data
+#'
+#' Dataset comes from an analysis of systematic reviews (SRs) and systematic maps (SM) published by the
+#' Collaboration for Environmental Evidence (CEE, www.environmentalevidence.org) between May 2012 and
+#' March 2017. Data are based on the empirical study of environmental systematic reviews by Haddaway
+#' and Westgate (2018) https://doi.org/10.1111/cobi.13231.
+#'
+#' @docType data
+#'
+#' @usage data(sampledata)
+#'
+#' @format An object of class \code{"cross"}; see \code{\link[qtl]{read.cross}}.
+#'
+#' @keywords datasets
+#'
+#' @references Haddaway and Westgate (2018) Conservation Biology, 33(2):434-443
+#' (\href{https://doi.org/10.1111/cobi.13231})
+#'
+#' @source \href{https://doi.org/10.1111/cobi.13231}
+#'
+#' @examples
+#' data(sampledata)
+#' str(sampledata)
+
+"sampledata"
diff --git a/data/sampledata.RData b/data/sampledata.RData
new file mode 100644
index 0000000..2d53d35
Binary files /dev/null and b/data/sampledata.RData differ
diff --git a/man/sampledata.Rd b/man/sampledata.Rd
new file mode 100644
index 0000000..1874d6e
--- /dev/null
+++ b/man/sampledata.Rd
@@ -0,0 +1,28 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/sampledata.R
+\docType{data}
+\name{sampledata}
+\alias{sampledata}
+\title{Systematic review sample data}
+\format{An object of class \code{"cross"}; see \code{\link[qtl]{read.cross}}.}
+\source{
+\href{https://doi.org/10.1111/cobi.13231}
+}
+\usage{
+data(sampledata)
+}
+\description{
+Dataset comes from an analysis of systematic reviews (SRs) and systematic maps (SM) published by the
+Collaboration for Environmental Evidence (CEE, www.environmentalevidence.org) between May 2012 and
+March 2017. Data are based on the empirical study of environmental systematic reviews by Haddaway
+and Westgate (2018) https://doi.org/10.1111/cobi.13231.
+}
+\examples{
+data(sampledata)
+str(sampledata)
+}
+\references{
+Haddaway and Westgate (2018) Conservation Biology, 33(2):434-443
+(\href{https://doi.org/10.1111/cobi.13231})
+}
+\keyword{datasets}
diff --git a/man/usedefaults.Rd b/man/usedefaults.Rd
index 21aa336..22ba70b 100644
--- a/man/usedefaults.Rd
+++ b/man/usedefaults.Rd
@@ -16,8 +16,9 @@ usedefaults(planning, protocol, administration, fte, databases, db.day,
   comms, meetings)
 }
 \description{
-This function takes an input dataset and imputes missing values for specific columns using
+This function uses an input dataset and imputes missing values for specific columns using
 empirically-derived default values. Default values are provided based on the empirical
 study of environmental systematic reviews by Haddaway and Westgate (2018)
-https://doi.org/10.1111/cobi.13231.
+https://doi.org/10.1111/cobi.13231. The function relies on the 'replace_na' function in
+the 'tidyr' package.
 }