As shown in Table  2, the proposed adaptive multi-pass decoder obtains an improvement about 0.41 to 0.5 BLEU on average over the {2,3,4,5}-pass decoder, which demonstrates the effectiveness of the policy network.
the adaptive multi-pass decoder outperforms the multi-pass decoder with a fixed decoding depth by 0.69, 0.71, 0.68 and 0.45 BLEU scores on NIST03, NIST04, NIST05 and NIST06 datasets at most.