diff --git a/matlab/set_state_space.m b/matlab/set_state_space.m
index 00fa0d66f2672c4a75bf4c8c3441c14cffc38438..02705a893324e17a22a8ffc5da45e72f6b4c915d 100644
--- a/matlab/set_state_space.m
+++ b/matlab/set_state_space.m
@@ -112,6 +112,6 @@ dr.nfwrd = nfwrd;
 % number of forward variables in the state vector
 dr.nsfwrd = nfwrd;
 % number of predetermined variables in the state vector
-dr.nspred = npred;
+dr.nspred = npred+nboth;
 
 dr.transition_auxiliary_variables = [];