Given a set of evaluation documents, each having a known correct label from a closed set of labels (often referred to as the “gold-standard”), and a predicted label for each document from the same set, the document-level accuracy is the proportion of documents that are correctly labeled over the entire evaluation collection. This is the most frequently reported metric and conveys the same information as the error rate, which is simply the proportion of documents that are incorrectly labeled (i.e. INLINEFORM0 ). There are two distinct ways in which results are generally summarized per-language: (1) precision, in which documents are grouped according to their predicted language; and (2) recall, in which documents are grouped according to what language they are actually written in. It is also common practice to report an F-score INLINEFORM0 , which is the harmonic mean of precision and recall. 
 Question: what evaluation methods are discussed?
document-level accuracy precision recall F-score