Rodgers Joseph Lee, Beasley William Howard, Schuelke Matthew
a Department of Psychology and Human Development , Vanderbilt University.
b University of Oklahoma Health Sciences Center.
Multivariate Behav Res. 2014 Nov-Dec;49(6):571-80. doi: 10.1080/00273171.2014.946589.
Many data structures, particularly time series data, are naturally seasonal, cyclical, or otherwise circular. Past graphical methods for time series have focused on linear plots. In this article, we move graphical analysis onto the circle. We focus on 2 particular methods, one old and one new. Rose diagrams are circular histograms and can be produced in several different forms using the RRose software system. In addition, we propose, develop, illustrate, and provide software support for a new circular graphical method, called Wrap-Around Time Series Plots (WATS Plots), which is a graphical method useful to support time series analyses in general but in particular in relation to interrupted time series designs. We illustrate the use of WATS Plots with an interrupted time series design evaluating the effect of the Oklahoma City bombing on birthrates in Oklahoma County during the 10 years surrounding the bombing of the Murrah Building in Oklahoma City. We compare WATS Plots with linear time series representations and overlay them with smoothing and error bands. Each method is shown to have advantages in relation to the other; in our example, the WATS Plots more clearly show the existence and effect size of the fertility differential.
许多数据结构，尤其是时间序列数据，本质上具有季节性、周期性或其他循环性。过去用于时间序列的图形方法主要集中在线性图上。在本文中，我们将图形分析转移到圆上。我们重点介绍两种特定方法，一种是旧方法，一种是新方法。玫瑰图是圆形直方图，可以使用RRose软件系统以几种不同形式生成。此外，我们提出、开发、说明并提供软件支持一种新的圆形图形方法，称为环绕时间序列图（WATS图），它是一种图形方法，通常有助于支持时间序列分析，特别是与中断时间序列设计相关的分析。我们用一个中断时间序列设计来说明WATS图的使用，该设计评估了俄克拉荷马城爆炸案对俄克拉荷马县在围绕俄克拉荷马城默拉大楼爆炸案的10年期间出生率的影响。我们将WATS图与线性时间序列表示进行比较，并将平滑线和误差带叠加在它们上面。结果表明，每种方法相对于另一种方法都有优势；在我们的例子中，WATS图更清楚地显示了生育率差异的存在和效应大小。
