He pioneered two important methods for investigating deep relationships between languages, lexicostatistics and glottochronology. This is the method used in Swadesh's original lexicostatistics. A leading exponent of lexicostatistics application has been Isidore Dyen. Beyond that, classification is based on lexicostatistics, which is generally unreliable. A combination of the various improvements is given in Sankoff's "Fully Parameterised Lexicostatistics". The term "lexicostatistics" is misleading in that mathematical equations are used but not statistics. Earlier methods, such as lexicostatistics and glottochronology, have been proven to be premature and inaccurate. It has been used in lexicostatistics by linguists such as Sergei Starostin. In lexicostatistics the features are the meanings of words, or rather semantic slots. Lexicostatistics has been used in defense of the traditional family tree. However, lexicostatistics does not rely on all the decisions being correct. He used lexicostatistics to classify Austronesian languages as well as Indo-European ones. Lexicostatistics is related to the comparative method but does not reconstruct a proto-language. Lexicostatistics is a distance-based method, whereas the comparative method considers language characters directly.