In the Control phase of Lean Six Sigma, the focus is on maintaining the improvements achieved during the Improve phase and ensuring that the process remains stable and capable of meeting customer requirements over time. Various charts, diagrams, and tools are utilized to monitor process performance, detect deviations, and implement corrective actions as needed. Here are some commonly used ones:

1. Control Charts: Control charts are one of the primary tools used in the Control phase. They monitor process performance over time by plotting data points against control limits. Control charts help distinguish between common cause variation (inherent to the process) and special cause variation (due to external factors or changes in the process). Common types of control charts include:
   • X-bar and R (or S) Charts: Used to monitor the central tendency and variation of a process over time.
   • Individuals and Moving Range (I-MR) Charts: Suitable for processes with one data point per time period, such as individual measurements or counts.
   • P Charts: Used for monitoring the proportion of defective items or occurrences in a process.
   • C Charts: Used for monitoring the count of defects or occurrences per unit of measurement.
2. Control Plan: A document outlining the actions, controls, and monitoring mechanisms to sustain the improvements achieved during the Improve phase. The control plan specifies who is responsible for monitoring process performance, how often monitoring will occur, and what actions will be taken if process performance deviates from the desired target.
3. Standard Operating Procedures (SOPs): Detailed instructions outlining the steps for performing specific tasks within the process. SOPs help ensure consistency and reproducibility in process execution, reducing the likelihood of errors and deviations.
4. Visual Management Tools: Visual management tools, such as visual controls, dashboards, and scorecards, provide a quick and easy way to monitor process performance and communicate key performance indicators (KPIs) to stakeholders. Visual management tools help keep the focus on continuous improvement and facilitate timely decision-making.
5. 5S (Sort, Set in order, Shine, Standardize, Sustain): A methodology for organizing the workplace to improve efficiency, productivity, and safety. 5S helps create a clean, organized, and standardized work environment, making it easier to identify and address deviations in process performance.
6. Gemba Walks: Gemba walks involve going to the actual location where work is done to observe processes, gather information, and engage with frontline employees. Gemba walks help leaders understand the current state of the process, identify improvement opportunities, and ensure that improvements are sustained over time.
7. Training and Development Programs: Ongoing training and development programs ensure that employees have the necessary skills and knowledge to perform their jobs effectively and contribute to process improvements. Training programs may include topics such as Lean Six Sigma methodologies, problem-solving techniques, and process-specific training.

These charts, diagrams, and tools help Lean Six Sigma teams monitor process performance, detect deviations, and implement corrective actions to maintain the improvements achieved during the Improve phase and ensure long-term success.