Based on these results, Brooke and Hirst (2011) argue that a strong content bias is present in ICLE, allowing an easy classification by topic instead of by native language.
it remains unclear whether the poor Lang-8 results are not due to the properties of this specific corpus, which seems to be highly heterogeneous and incoherent, and whether the poor cross-corpus evaluation results are of general importance or due to the nature of the Lang-8 corpus.