On the Effectiveness of Offline RL for Dialogue Response Generation

However, this can be expensive to collect. Instead, modelbased metrics to measure utterance similarity, such as A common training technique for language models BERTScore (Zhang et al., 2019) and BLEURT (Sellam is teacher forcing (TF). TF attempts to match et al., 2020), provide a cheaper alternative. These are automated human language exactly, even though identical metrics that capture semantic similarity between meanings can be expressed in different ways. This sentences and tend to have a high correlation with human motivates use of sequence-level objectives for dialogue judgment (Zhang et al., 2019; Sellam et al., 2020).