In a count measurement check, the reported count minus the independently established reference count.
Also called: count error; count deviation; miscount.
Positive and negative counting error
Here, counting error is the reported count minus an independently established reference count for the same observation. Positive means the indication is higher; negative means it is lower. The sign describes the count measurement, not automatically the final bottle’s relation to its fill target.
The reference count establishes what was present; the target states what was intended. Use the former to calculate indication error and the latter to assess underfill or overfill.
Yes. Signed differences can cancel when averaged. In an illustrative pair of observations, errors of +1 and −1 piece average to zero, although neither count agrees with its reference. An average signed result alone cannot show how many observations were exact.
Report how many observations agreed with the reference as well as any signed average. Define each observation consistently as an item event, batch or bottle.
Does an error value identify the cause of a miscount?
The difference records disagreement with the reference. It does not identify which event was missed, counted twice or assigned to another container. Establishing a cause requires additional observation of the sensing and handling functions involved.
An error record becomes useful for investigation when it includes the indicated count, reference count, fill target and receiving bottle.