The normalized pairwise variability index (nPVI) is a measure originally used to compare the rhythms of languages. Patel and Daniele (2003a) introduced the nPVI to music research and it has since been used in a number of studies. In this paper, I present a methodological criticism of the nPVI as applied to music. I discuss the known qualitative features of the nPVI and illustrate the nPVI9s fundamental features and assumptions through its application to a number of musical datasets. My principle criticism regards the application of a linear average (the nPVI) to categorical data (rhythmic notation). I argue that that simpler mathematical characterizations, which are more musically intuitive, can capture the same useful information as the nPVI. Specifically, counting the proportion of successive IOIs that are identical accounts for as much as 98% of variation in nPVIs in musical corpora. I argue that abstract mathematical measures ought to be avoided in preference for more concrete empirical descriptions of specific rhythmic features, and that, rather than focusing on a single measure, multiple measures ought to be used. Finally, I conclude that the usage of nPVI in music research should be limited to specific methodologically justified contexts.

中文翻译：

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解构nPVI

标准化的成对变异性指数（nPVI）是最初用于比较语言节奏的一种度量。Patel和Daniele（2003a）将nPVI引入音乐研究，此后已在许多研究中使用。在本文中，我对音乐中的nPVI提出了方法学上的批评。我讨论了nPVI的已知定性特征，并通过将nPVI9应用于许多音乐数据集来说明其基本特征和假设。我的主要批评意见涉及将线性平均值（nPVI）应用于分类数据（节奏符号）。我认为，更简单的数学特征（在音乐上更直观）可以捕获与nPVI相同的有用信息。特别，计算连续相同的IOI的比例，占音乐语料库nPVI差异的98％。我认为应该优先使用抽象的数学测量方法，而不要对具体的节奏特征进行更具体的经验描述，并且应该使用多种测量方法，而不是只关注一种测量方法。最后，我得出结论，在音乐研究中nPVI的使用应限于特定的方法论上合理的背景。