Why do we still use 18-year old BLEU?
NLP technology has changed and advanced over the past two decades, but it often seems that NLG evaluation has not. Why is the 18-year old BLEU metric still so dominant?
Tag: BLEU
Evaluation Grand Challenge: Is NLP System Good Enough for a Use Case?
I was recently asked by someone if it was possible to easily determine whether an NLP system was good enough for a specific use case. Currently this is very hard. Making it easy could be a “grand challenge” for evaluation!
Hallucination in Neural NLG
Many neural NLG systems “hallucinate” non-existent or incorrect content. This is a major problem, since such hallucination is unacceptable in many (most?) NLG use cases. Also BLEU and related metrics do not detect hallucination well, so researchers who rely on such metrics may be misled about the quality of their system.
How to Validate Metrics
My advice on how to perform a high-quality validation study, which assesses whether a metric (such as BLEU) correlates well with human evaluations.
Why doesnt BLEU work for NLG?
BLEU works much better for MT systems and NLG systems. In this blog I present some speculations as to why this is the case.
BLEU in Different Languages: Dont use it for German
My structured survey of BLEU suggests that BLEU-human correlations are worse in German than in many other languages. But there are many caveats, so we need to be cautious in interpreting this result.
BLEU-Human Correlation is Increasing: What does this Mean?
The correlation between BLEU and human evaluations of MT systems seems to be increasing over time. Since BLEU has not changed, how is this possible, and what does it mean?
Is BLEU valid? First observations and concerns
The first phase of my systematic review of BLEU shows that BLEU-human correlations are all over the place, and that none of the studies in my review have correlated BLEU with real-world utility or user satisfaction.
Study Design for Systematic Review of BLEU Validity: Comments Welcome!
I’m planning to do a systematic review of the validity of BLEU, and am very keen to get comments and suggestions on study design from others!
