Levey-Jennings chart 438871 220895973 2008-06-22T03:12:26Z SmackBot 433328 Date the maintenance tags or general fixes {{Orphan|date=May 2008}} {{Mergeto|Laboratory Quality Control|date=June 2008}} [[Image:Levey-Jennings SampleChart.jpg|frame|right||A sample Levey-Jennings chart.]] A '''Levey-Jennings chart''' is a graph that [[quality control]] data is plotted on to give a visual indication whether a laboratory test is working well. On the x-axis the date and time, or more usually the number of the control run, are plotted. A mark is made indicating how far off the actual result was from the mean (which is the expected value for the control). The distance from the mean is measured in [[standard deviation]]s (SD). Lines run across the graph at the mean, as well as one, two and sometimes three standard deviations either side of the mean. This makes it easy to see how far off the result was. Rules, such as the [[Westgard rules]] can be applied to see whether the results from the samples when the control was done can be released, or if they need to be rerun. ==External links== *[http://www.westgard.com Westgard Q C] [[Category:Quality control]] {{statistics-stub}}