Knowledge Guided Text Retrieval and Reading for Open Domain Question Answering
Table 5: Comparison to passage concatenation. For all rows, GraphRetriever is used.
['[EMPTY]', '[BOLD] WebQ', '[BOLD] Natural Q']
First, ParReader++ (pairs from graph) concatenates passage pairs that are related in the input graph, along with the relation text. Second, ParReader++ (all pairs) concatenates all passage pairs. For these baselines, the concatenated passages are up to 300 tokens. For ParReader++ (pairs from graph), we use n=20 instead of n={40,80}. It is worth noting that concatenating more passages into a single input is non-trivial due to the fixed input length of BERT. Results show that concatenating passages is not competitive, potentially because truncating each passage causes significant information loss.