Compare Against Specification Limits
To extract even more valuable information, box-and-whisker plots can be compared against specification limits. This allows the viewer to understand which data sets are generating the most (and least) out-of-specification issues. As a result, box-and-whisker plots are ideal tools for prioritizing quality activities and Six Sigma projects.
Compare Multiple Process Streams
Box-and-whisker plots are particularly useful for viewing the performance of multiple process streams in the same interface. This capability is useful in any industry that needs to compare performance between production lines, product codes, and shifts.
For example, in food packaging organizations, minimum fill weights are regulated. Underfilling can result in fines or sanctions; overfilling can significantly increase costs.
Box-and-whisker plots quickly reveal vitally important information such as:
- Whether products are being filled to minimum required levels
- The presence and amount of overfill
- Which products run best on which production lines
- Which production lines run the same product weights higher (or lower) than others
- Whether different shifts fill consistently
- Average fill volumes
- Variability in fill volumes
- Where out-of-specification issues occur the most