A New Engineering Graph for Pharmaceutical Processes

The author proposes a new analytical graphic, the sector chart, which presents data that cannot be adequately presented with current graphs. This chart combines features of zone charts with the basic principle of precontrol charts. It addresses engineering control and is superior for representing data such as beneficial and adverse trends. simple analytical graphic is the time plot. The reportable value for the response variable is scaled on the vertical axis and time in some metric is represented on the horizontal axis. Time plots are powerful tools for observing and understanding process changes or lack of change over time. These plots make no assumptions about the data except that the data are collected sequentially over time. Time plots, when used by a knowledgeable and experienced analyst, are the best first step in an analysis of data collected over time. Beyond a time plot, the classic Shewhart statistical control chart is best known and most widely used. First presented by Walter A. Shewhart, PhD, in 1924 in an internal memorandum at Barr Labs, it has become, all too often, the default choice for any type of data taken over time. Shewhart charts are excellent for their intended use but inadequate for many situations.