### Doc2Query−−: When Less is More

You might notice that not all the generated queries look related to the source text. This is due
to a defect that can appear in sequence-to-sequence models known as "[hallucination](https://aclanthology.org/2020.acl-main.173/)".

Doc2Query−− can filter out these low-quality queries by measuring the relevance between them and the text that
generated them using a scoring transformer `S`. It is applied as two transformers that follow the Doc2Query generator:

<div class="pipeline">
  <div class="df" title="Document Frame">D</div>
  <div class="transformer" title="Doc2Query Transformer">Doc2Query</div>
  <div class="df" title="Document Frame">D</div>
  <div class="transformer attn" title="Doc2Query Transformer">QueryScorer
    <div class="artefact" title="Scorer Transformer">S</div>
  </div>
  <div class="df" title="Document Frame">D</div>
  <div class="transformer attn" title="Doc2Query Transformer">QueryFilter</div>
  <div class="df" title="Document Frame">D</div>
</div>