Reading Your Dashboard
Control Charts (X-mR)
Control charts show your measurement data plotted over time with statistically calculated limits. They help you distinguish normal variation from special causes.
- Center Line (CL) -- The average of your measurements. This is where a stable process centers.
- Upper/Lower Control Limits (UCL/LCL) -- Calculated at 3 sigma from the center line. Points within these limits are normal variation.
- Out-of-Control Points -- Points beyond the control limits or violating run rules indicate a special cause that should be investigated.
Capability Indices
Capability indices measure how well your process fits within specification limits. They require Upper and Lower Specification Limits (USL/LSL) to calculate.
| Index | What it Measures | Good Value |
|---|---|---|
| Cp | Process potential -- how much spread fits within spec limits (ignoring centering) | ≥ 1.33 |
| Cpk | Process capability -- like Cp but accounts for how centered the process is | ≥ 1.33 |
| Pp / Ppk | Process performance -- similar to Cp/Cpk but uses overall standard deviation | ≥ 1.33 |
Box Plots
Box plots show the distribution of your data. The box spans the middle 50% (Q1 to Q3), the line inside is the median, and whiskers extend to the most extreme non-outlier values. Dots beyond the whiskers are outliers.
Insights Panel
The insights panel highlights key findings automatically: which group has the best/worst capability, which has the most variation, and any out-of-control conditions detected.