One can conceive a two-pass scenario where we first make a binary decision of whether there is an empty category associated with the head in the first pass and then determine whether there is an EC associated with the tuple as well as the EC type in the second pass.
dev Test 81-325, 400-454, 500-554 41-80 1-40 590-596, 600-885, 900 901-931 As discussed in Section 2, the gold standard dependency structure parses are converted from the CTB parse trees, with the ECs preserved.