diff --git a/matlab/var_sample_moments.m b/matlab/var_sample_moments.m
index ab7b4b74b6575b2be7d6d04ba19593ae560b3495..434a2032e894171c1aa951ca8fba1623b54088f0 100644
--- a/matlab/var_sample_moments.m
+++ b/matlab/var_sample_moments.m
@@ -77,8 +77,10 @@ XtX = [];
 
 data = read_variables(datafile,varobs,[],xls_sheet,xls_range);
 
-if qlag > FirstObservation
-    error('VarSampleMoments :: not enough data to initialize! Try to increase FirstObservation.')
+if qlag >= FirstObservation
+    fprintf('\nVarSampleMoments: The first used observation is %d, but there are %d lags.\n',FirstObservation,qlag)
+    fprintf('VarSampleMoments: Try to increase first_obs. Given the lags, it must be at least first_obs=%d.\n',qlag+1)
+    error('VarSampleMoments :: not enough data to initialize!')
     return
 end