diff --git a/matlab/dynare_sensitivity.m b/matlab/dynare_sensitivity.m
index 182c2214974b4a5814ae312022ca79761ce95519..1d9eeef7f5fadf1f3e8187bdcc3a074753ef61f8 100644
--- a/matlab/dynare_sensitivity.m
+++ b/matlab/dynare_sensitivity.m
@@ -154,7 +154,7 @@ options_gsa = set_default_option(options_gsa,'namlagendo',[]);
 options_gsa = set_default_option(options_gsa,'namexo',[]);
 % RMSE mapping
 options_gsa = set_default_option(options_gsa,'lik_only',0);
-options_gsa = set_default_option(options_gsa,'var_rmse',options_.varobs);
+options_gsa = set_default_option(options_gsa,'var_rmse',char(options_.varobs));
 options_gsa = set_default_option(options_gsa,'pfilt_rmse',0.1);
 options_gsa = set_default_option(options_gsa,'istart_rmse',options_.presample+1);
 options_gsa = set_default_option(options_gsa,'alpha_rmse',0.001);