Anhøj Jacob, Olesen Anne Vingaard
Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
University of Aalborg, Danish Center for Healthcare Improvements, Department of Business and Management, Aalborg, Denmark.
PLoS One. 2014 Nov 25;9(11):e113825. doi: 10.1371/journal.pone.0113825. eCollection 2014.
A run chart is a line graph of a measure plotted over time with the median as a horizontal line. The main purpose of the run chart is to identify process improvement or degradation, which may be detected by statistical tests for non-random patterns in the data sequence.
We studied the sensitivity to shifts and linear drifts in simulated processes using the shift, crossings and trend rules for detecting non-random variation in run charts.
The shift and crossings rules are effective in detecting shifts and drifts in process centre over time while keeping the false signal rate constant around 5% and independent of the number of data points in the chart. The trend rule is virtually useless for detection of linear drift over time, the purpose it was intended for.
运行图是一种折线图,展示了随时间变化的测量值,并以中位数作为一条水平线。运行图的主要目的是识别过程的改进或退化,这可以通过对数据序列中的非随机模式进行统计检验来检测。
我们使用运行图中检测非随机变化的偏移、交叉和趋势规则,研究了模拟过程中对偏移和线性漂移的敏感性。
偏移和交叉规则在检测过程中心随时间的偏移和漂移方面是有效的,同时将误报率保持在5%左右且与图中的数据点数无关。趋势规则对于检测其原本 intended 用于的随时间的线性漂移几乎毫无用处。