diff --git a/matlab/reports/@graph/graph.m b/matlab/reports/@graph/graph.m
index 5f4a2343c4680f0387d6a12852e776ce6b8fdd10..6873043975908f888796b2416549c3038bd916af 100644
--- a/matlab/reports/@graph/graph.m
+++ b/matlab/reports/@graph/graph.m
@@ -156,7 +156,7 @@ assert(isempty(o.yrange) || (isfloat(o.yrange) && length(o.yrange) == 2 && ...
                              o.yrange(1) < o.yrange(2)), ...
        ['@graph.graph: yrange is specified an array with two float entries, ' ...
         'the lower bound and upper bound.']);
-assert(isempty(o.data) || isa(o.data, 'dseries'), ['@graph.graph: data must ' ...
+assert(isempty(o.data) || isdseries(o.data), ['@graph.graph: data must ' ...
                     'be a dseries']);
 assert(isempty(o.seriesToUse) || iscellstr(o.seriesToUse), ['@graph.graph: ' ...
                     'seriesToUse must be a cell array of string(s)']);
diff --git a/matlab/reports/@report_series/writeSeriesForGraph.m b/matlab/reports/@report_series/writeSeriesForGraph.m
index 61afce9a9b9ee6586bc3651bc4d2b8cb535c7d0a..93c08de4ef929aa95ca9df1efcc78599f158b4e9 100644
--- a/matlab/reports/@report_series/writeSeriesForGraph.m
+++ b/matlab/reports/@report_series/writeSeriesForGraph.m
@@ -31,7 +31,7 @@ function o = writeSeriesForGraph(o, fid, xrange)
 
 %% Validate options provided by user
 if isempty(o.graphVline) && isempty(o.graphHline)
-    assert(~isempty(o.data) && isa(o.data, 'dseries'), ['@report_series.writeSeriesForGraph: must ' ...
+    assert(~isempty(o.data) && isdseries(o.data), ['@report_series.writeSeriesForGraph: must ' ...
                         'provide data as a dseries']);
 end
 
diff --git a/matlab/reports/@report_series/writeSeriesForTable.m b/matlab/reports/@report_series/writeSeriesForTable.m
index a3999c566611bc227b87d9a09ea445c0e881c8e6..2ef3e884589b48140fbb13ac12fde07809e4e165 100644
--- a/matlab/reports/@report_series/writeSeriesForTable.m
+++ b/matlab/reports/@report_series/writeSeriesForTable.m
@@ -42,11 +42,11 @@ assert(isint(precision));
 %% Validate options provided by user
 assert(ischar(o.tableSubSectionHeader), '@report_series.writeSeriesForTable: tableSubSectionHeader must be a string');
 if isempty(o.tableSubSectionHeader)
-    assert(~isempty(o.data) && isa(o.data, 'dseries'), ...
+    assert(~isempty(o.data) && isdseries(o.data), ...
            '@report_series.writeSeriesForTable: must provide data as a dseries');
 
     if ~isempty(o.tableDataRhs)
-        assert(~isempty(o.tableDataRhs) && isa(o.tableDataRhs, 'dseries'), ...
+        assert(~isempty(o.tableDataRhs) && isdseries(o.tableDataRhs), ...
                '@report_series.writeSeriesForTable: must provide tableDataRhs as a dseries');
         assert(iscell(dates) && length(dates) == 2, ...
                '@report_series.writeSeriesForTable: must provide second range with tableDataRhs');
diff --git a/matlab/reports/@report_table/report_table.m b/matlab/reports/@report_table/report_table.m
index 70b17c9ffbe8ac763856fad76972115a08bd2352..3fc1e2a7d35c536e73ca3d42976b94afea8e7c92 100644
--- a/matlab/reports/@report_table/report_table.m
+++ b/matlab/reports/@report_table/report_table.m
@@ -98,7 +98,7 @@ assert(isint(o.precision), '@report_table.report_table: precision must be an int
 assert(isempty(o.range) || length(o.range) <=2 && allCellsAreDatesRange(o.range), ...
        ['@report_table.report_table: range is specified as a dates range, e.g. ' ...
         '''dates(''1999q1''):dates(''1999q3'')''.']);
-assert(isempty(o.data) || isa(o.data, 'dseries'), ...
+assert(isempty(o.data) || isdseries(o.data), ...
        '@report_table.report_table: data must be a dseries');
 assert(isempty(o.seriesToUse) || iscellstr(o.seriesToUse), ...
        '@report_table.report_table: seriesToUse must be a cell array of string(s)');
diff --git a/matlab/reports/display_reporting_object.m b/matlab/reports/display_reporting_object.m
index e8ae950e4aa2d5423009c9394194c41a480ae30e..9db3bd770dfecb198cfc69b0d432dbd46d6b4955 100644
--- a/matlab/reports/display_reporting_object.m
+++ b/matlab/reports/display_reporting_object.m
@@ -72,7 +72,7 @@ for i=1:length(fields)
         if isdates(val)
             fprintf('<dates: %s, ..., %s>', ...
                     date2string(val(1)), date2string(val(end)));
-        elseif isa(val, 'dseries')
+        elseif isdseries(val)
             if numel(val) == 1
                 fprintf('<dseries: %s>', val.name{1});
             else