diff --git a/NAMESPACE b/NAMESPACE
index b10a82b..a7bd27e 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -1,5 +1,6 @@
 # Generated by roxygen2: do not edit by hand
 
+S3method(rbind,cohortDefinitionSet)
 export(CohortSubsetDefinition)
 export(CohortSubsetOperator)
 export(DemographicSubsetOperator)
diff --git a/R/CohortConstruction.R b/R/CohortConstruction.R
index 2c39889..e04648e 100644
--- a/R/CohortConstruction.R
+++ b/R/CohortConstruction.R
@@ -58,16 +58,17 @@
 #'    }
 #'
 #' @export
-generateCohortSet <- function(connectionDetails = NULL,
+generateCohortSet <- function(cohortDefinitionSet,
+                              connectionDetails = NULL,
                               connection = NULL,
                               cdmDatabaseSchema,
                               tempEmulationSchema = getOption("sqlRenderTempEmulationSchema"),
                               cohortDatabaseSchema = cdmDatabaseSchema,
                               cohortTableNames = getCohortTableNames(),
-                              cohortDefinitionSet = NULL,
                               stopOnError = TRUE,
                               incremental = FALSE,
                               incrementalFolder = NULL) {
+  cohortDefinitionSet <- as.cohortDefinitionSet(cohortDefinitionSet)
   checkmate::assertDataFrame(cohortDefinitionSet, min.rows = 1, col.names = "named")
   checkmate::assertNames(colnames(cohortDefinitionSet),
     must.include = c(
diff --git a/R/CohortDefinitionSet.R b/R/CohortDefinitionSet.R
index 29ad78b..278c98a 100644
--- a/R/CohortDefinitionSet.R
+++ b/R/CohortDefinitionSet.R
@@ -21,22 +21,14 @@ as.cohortDefinitionSet <- function(df) {
   invisible(df)
 }
 
-# Define the cohortDefinitionSet class
-setClass("cohortDefinitionSet", contains = "data.frame")
+#' @export
+rbind.cohortDefinitionSet <- function(...) {
+  print('foo')
+  base::rbind.default(...)
 
-# Create a constructor for cohortDefinitionSet
-cohortDefinitionSet <- function(...) {
-  obj <- new("cohortDefinitionSet", ...)
-  obj
+  return(NULL)
 }
 
-# Override the rbind method for cohortDefinitionSet
-setMethod("rbind", signature(x = "cohortDefinitionSet", y = "cohortDefinitionSet"), function(x, y, ...) {
-  # Custom logic to combine two cohortDefinitionSet objects
-  combined_set <- data.frame(rbind(as.data.frame(x), as.data.frame(y)))
-  return(combined_set)
-})
-
 #' Create an empty cohort definition set
 #'
 #' @description
diff --git a/man/createCohortSubsetDefinition.Rd b/man/createCohortSubsetDefinition.Rd
index 6046b77..4076174 100644
--- a/man/createCohortSubsetDefinition.Rd
+++ b/man/createCohortSubsetDefinition.Rd
@@ -23,12 +23,12 @@ createCohortSubsetDefinition(
 \item{identifierExpression}{Expression (or string that converts to expression) that returns an id for an output cohort
 the default is dplyr::expr(targetId * 1000 + definitionId)}
 
-\item{operatorNameConcatString}{(optional) SqlRender string template for formatting names of resulting subset cohorts
+\item{operatorNameConcatString}{(optional) String to concatenate operator names together when outputting resulting cohort
+name}
+
+\item{subsetCohortNameTemplate}{(optional) SqlRender string template for formatting names of resulting subset cohorts
 Can use the variables @baseCohortName, @subsetDefinitionName and @operatorNames.
 This is applied when adding the subset definition to a cohort definition set.}
-
-\item{subsetCohortNameTemplate}{(optional) String to concatenate operator names together when outputting resulting cohort
-name}
 }
 \description{
 Create subset definition from subset objects
diff --git a/man/generateCohortSet.Rd b/man/generateCohortSet.Rd
index ba4609e..632edcb 100644
--- a/man/generateCohortSet.Rd
+++ b/man/generateCohortSet.Rd
@@ -5,19 +5,27 @@
 \title{Generate a set of cohorts}
 \usage{
 generateCohortSet(
+  cohortDefinitionSet,
   connectionDetails = NULL,
   connection = NULL,
   cdmDatabaseSchema,
   tempEmulationSchema = getOption("sqlRenderTempEmulationSchema"),
   cohortDatabaseSchema = cdmDatabaseSchema,
   cohortTableNames = getCohortTableNames(),
-  cohortDefinitionSet = NULL,
   stopOnError = TRUE,
   incremental = FALSE,
   incrementalFolder = NULL
 )
 }
 \arguments{
+\item{cohortDefinitionSet}{The \code{cohortDefinitionSet} argument must be a data frame with 
+the following columns: \describe{
+\item{cohortId}{The unique integer identifier of the cohort} 
+\item{cohortName}{The cohort's name}
+\item{sql}{The OHDSI-SQL used to generate the cohort}}
+Optionally, this data frame may contain: \describe{
+\item{json}{The Circe JSON representation of the cohort}}}
+
 \item{connectionDetails}{An object of type \code{connectionDetails} as created using the
 \code{\link[DatabaseConnector]{createConnectionDetails}} function in the
 DatabaseConnector package. Can be left NULL if \code{connection} is
@@ -44,14 +52,6 @@ this should include both the database and schema name, for example
 \item{cohortTableNames}{The names of the cohort tables. See \code{\link{getCohortTableNames}}
 for more details.}
 
-\item{cohortDefinitionSet}{The \code{cohortDefinitionSet} argument must be a data frame with 
-the following columns: \describe{
-\item{cohortId}{The unique integer identifier of the cohort} 
-\item{cohortName}{The cohort's name}
-\item{sql}{The OHDSI-SQL used to generate the cohort}}
-Optionally, this data frame may contain: \describe{
-\item{json}{The Circe JSON representation of the cohort}}}
-
 \item{stopOnError}{If an error happens while generating one of the cohorts in the
 cohortDefinitionSet, should we stop processing the other
 cohorts? The default is TRUE; when set to FALSE, failures will