A measurement system (gauge) that injects a lot of variation from the gauge (or operator) into the variation of the measurement of the object being measured might be thought of as being "wobbly". Too much wobble (variation from the gauge or operator) makes it difficult to get reliable data.
Simulated gyroscope (top).
Learning point: the lines of the boundary cube might be presented as the specification limits of the object being measured. Run the simulation several times with varying amounts of wobble.
Low wobble results in a higher "ndc" (number of distinct categories) that the gauge can resolve across the width of the tolerance.
A large amount of wobble results in a lower ndc, similar to a gauge with poor R&R.
Video of four spinning tops with varying wobble.