Nearest-neighbor analysis (NNA)—a method for assessing the degree to which a spatial point pattern departs from randomness in the direction of being either clustered or regular—was imported into academic geography from an article published in 1954 by ecologists Clark and Evans. In its simplest form, concerned with distances to the first nearest neighbor, NNA hinged on the behavior of the “nearest-neighbour statistic,” R_n, supposed to vary between 0 (complete clustering) and 2.15 (complete regularity). NNA and the wider body of work on point pattern analysis quickly gained in sophistication, meaning that this simple test statistic only featured briefly in the frontline research literature of geographical analysis. Nonetheless, given its easy-to-grasp logic, it became and remains a staple of quantitative geography textbooks for undergraduate students and statistical methods training in school-level geography curricula. The purpose of this paper is to chart the history of NNA and its test statistic in academic geography, and to provide an analytical demonstration that the value of 2.15 has been mistakenly identified as an upper limit for the latter. Broader speculations are then offered about what may be learned from the history of how the discipline has handled this statistic.

中文翻译：

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2.15 还是不是 2.15？最近邻统计的历史分析探究

最近邻分析（NNA）——一种评估空间点模式在集群或规则方向上偏离随机性程度的方法——从生态学家克拉克和埃文斯于 1954 年发表的一篇文章中被引入到学术地理学中。NNA 最简单的形式涉及到第一个最近邻的距离，它取决于“最近邻统计”的行为，即R _n，应该在 0（完全聚类）和 2.15（完全规律）之间变化。NNA 和更广泛的点模式分析工作迅速变得更加复杂，这意味着这个简单的检验统计量仅在地理分析的前沿研究文献中出现过短暂的特征。尽管如此，由于其易于掌握的逻辑，它已成为并且仍然是本科生定量地理教科书和学校地理课程中统计方法培训的主要内容。本文的目的是绘制 NNA 的历史及其在学术地理学中的测试统计，并提供分析证明 2.15 的值已被错误地确定为后者的上限。