During the Measure phase of Lean Six Sigma, the focus is on collecting data to understand the current state of the process and establish a baseline for improvement. Various charts, diagrams, and tools are used to quantify process performance, identify sources of variation, and ensure the reliability of the measurement system. Here are some commonly used ones:

1. Check Sheets: Check sheets are simple data collection tools used to tally the frequency or occurrence of specific events or defects. They provide a structured format for collecting data in real-time and help identify patterns or trends in the data.
2. Data Collection Plan: A document outlining the methods and procedures for collecting data during the Measure phase. The data collection plan specifies what data will be collected, how it will be collected, who will collect it, and when it will be collected.
3. Process Maps (or Flowcharts): Visual representations of the steps in a process, used to identify inputs, outputs, activities, and decision points. Process maps help clarify the process flow and identify areas for data collection.
4. Sampling Plans: Techniques for selecting a representative subset of data from a larger population. Sampling plans help ensure that the data collected during the Measure phase accurately reflects the overall process performance.
5. Measurement System Analysis (MSA): A set of techniques used to assess the reliability and accuracy of the measurement system. MSA ensures that the data collected during the Measure phase is valid and trustworthy. Common MSA tools include:

• Gage R&R (Repeatability and Reproducibility): A study to evaluate the variability introduced by the measurement system itself.
• Bias Studies: Assessments of systematic errors or biases in the measurement system.
• Linearity Studies: Evaluations of the linearity of the measurement system across its operating range.

1. Control Charts: While primarily used in the Analyze and Control phases, control charts can also be employed during the Measure phase to monitor process stability and variability over time.
2. Histograms: Graphical representations of the distribution of data, showing the frequency or count of observations within specified ranges. Histograms help visualize the variation present in the process data collected during the Measure phase.
3. Box Plots: Another graphical tool for visualizing the distribution of data, particularly useful for identifying outliers and understanding the spread of data.

These charts, diagrams, and tools help Lean Six Sigma practitioners gather relevant data, assess the measurement system, and establish a solid foundation for subsequent phases of the improvement project.