Fix #760

Signed-off-by: Keith Battocchi <kebatt@microsoft.com>

econml/_ortho_learner.py

@@ -899,7 +899,7 @@ class _OrthoLearner(TreatmentExpansionMixin, LinearCateEstimator):
                     nuisances = [np.zeros((n_iters * n_splits,) + nuis.shape) for nuis in nuisance_temp]
 
                 for it, nuis in enumerate(nuisance_temp):
-                    nuisances[it][i * n_iters + j] = nuis
+                    nuisances[it][j * n_iters + i] = nuis
 
         for it in range(len(nuisances)):
             nuisances[it] = np.mean(nuisances[it], axis=0)

econml/tests/test_dml.py

@@ -1095,6 +1095,7 @@ class TestDML(unittest.TestCase):
                 est.fit(y, T, X=X, W=W)
                 assert len(est.nuisance_scores_t) == len(est.nuisance_scores_y) == mc_iters
                 assert len(est.nuisance_scores_t[0]) == len(est.nuisance_scores_y[0]) == cv
+                est.score(y, T, X=X, W=W)
 
     def test_categories(self):
         dmls = [LinearDML, SparseLinearDML]