  We introduce EASSE, a Python package aiming to facilitate and standardise
automatic evaluation and comparison of Sentence Simplification (SS) systems.
EASSE provides a single access point to a broad range of evaluation resources:
standard automatic metrics for assessing SS outputs (e.g. SARI), word-level
accuracy scores for certain simplification transformations,
reference-independent quality estimation features (e.g. compression ratio), and
standard test data for SS evaluation (e.g. TurkCorpus). Finally, EASSE
generates easy-to-visualise reports on the various metrics and features above
and on how a particular SS output fares against reference simplifications.
Through experiments, we show that these functionalities allow for better
comparison and understanding of the performance of SS systems.
