Empirical Evaluation of Tree distances for Parser Evaluation

In this empirical study, I compare various tree distance measures – originally developed in computational biology for the purpose of tree comparison – for the purpose of parser evaluation. I will control for the parser setting by comparing the automatically generated parse trees from the stateof-the-art parser (Charniak, 2000) with the gold-standard parse trees. The article describes two different tree distance measures (RF and QD) along with its variants (GRF and GQD) for the purpose of parser evaluation. The article will argue that RF measure captures similar information as the standard EvalB metric (Sekine and Collins, 1997) and the tree edit distance (Zhang and Shasha, 1989) applied by Tsarfaty et al. (2011). Finally, the article also provides empirical evidence by reporting high correlations between the different tree distances and EvalB metric’s scores.