Before revision:  To better assess the faithfulness of the machine outputs , we propose a new task to predict whether each token in the output sequence is hallucinated conditioned on the source input, and collect new manually annotated evaluation sets for this task.
After revision:  To better assess the faithfulness of the machine outputs , we propose a new task to predict whether each token in the output sequence is hallucinated (not contained in the input) and collect new manually annotated evaluation sets for this task.