Chunky data can distort your computations and result in an erroneous interpretation of your data. This column explains the signs of chunky data, outlines the nature of the problem that causes it, and suggests what to do when it occurs.

When the measurement increments used are too large for the job, the limits on a process behavior chart, as well as other statistical techniques, can be distorted. This distortion can lead to spurious results. Fortunately, this problem is easily detected by ordinary, production-line process behavior charts. No special studies are necessary; no standard parts or batches are needed. You simply need to recognize the telltale signs.

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