How do you communicate and present the results of Shewhart and CUSUM charts to stakeholders and clients?

1 Shewhart charts

Shewhart charts, also known as X-bar and R charts, are based on the assumption that the process variation follows a normal distribution and is stable over time. These charts consist of a central line representing the average of the process, and upper and lower control limits calculated from the standard deviation of the process. The chart displays sample means and ranges of the process over time, signaling when the process is out of control or exhibits unusual patterns. To communicate and present these results, you should explain the purpose and logic of the chart, how the central line and control limits are derived, highlight any points outside the control limits or indicating non-random variation (such as trends, cycles, or shifts), interpret the meaning and implications of these signals, suggest possible causes and corrective actions, and emphasize the benefits of using Shewhart charts to detect and prevent problems while improving process quality and efficiency.

2 CUSUM charts

CUSUM charts, or cumulative sum charts, are designed to detect small and persistent changes in the process mean that may not be noticeable in Shewhart charts. They plot the cumulative sum of the deviations of the process from a target value over time, and use decision intervals to indicate when a change has occurred. It is important to explain the purpose and logic of the chart, as well as how the target value and decision intervals are determined. Additionally, any points or segments that cross the decision intervals or show a significant slope or direction change should be highlighted. It is also necessary to interpret the meaning and implications of these signals, and estimate the magnitude and timing of the change. Lastly, it is essential to emphasize the benefits of using the chart to monitor and control the process mean, and to identify and eliminate sources of variation.

3 Choosing between Shewhart and CUSUM charts

When selecting between Shewhart and CUSUM charts for your process, you should consider the type and size of variation you want to detect, the frequency and cost of sampling and analysis, the complexity and clarity of the chart, and the preferences and expectations of your stakeholders. Shewhart charts are better at detecting large, sudden changes while CUSUM charts are more sensitive to small, gradual changes. Additionally, Shewhart charts require more samples and calculations than CUSUM charts, but they also provide more information and feedback on the process variation. Furthermore, Shewhart charts are easier to construct and interpret than CUSUM charts; however, they may be more cluttered and noisy. Ultimately, you should take into account the level of familiarity and comfort with the charts of your stakeholders, as well as their needs and interests in the process outcomes.

4 Preparing and delivering your presentation

Once you have chosen and prepared your control charts, you need to plan and deliver your presentation to your stakeholders and clients in a way that engages them and conveys your message effectively. To do this, it's important to know your audience, have a clear structure, use visual aids, practice and rehearse, and seek feedback. Tailor the presentation to the background, knowledge, goals, and concerns of the audience. Organize your presentation into an introduction, a body, and a conclusion. Include slides, graphs, tables, images, or videos to support your verbal presentation. Make sure the visual aids are clear, relevant, consistent, and accurate. Practice your presentation several times before delivering it. After the presentation is finished, ask for feedback from the audience or peers. Evaluate your strengths and weaknesses and identify areas for improvement.

5 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?