Evaluation of Three Methods for Inspection of Multiple Defects/Item

Abstract

An inspector can inspect an item once looking for multiple defects (e.g., scratches, color, shape) or look at the item once for scratches, once for color and once for shape. When should each strategy be used? Six non-student females inspected, at their own pace, a series of matrices with five types of defects: presence of A, B, $, 345 in a row and 678 in a row. Condition 1 was inspection of all matrices for one defect (say A), then all for a second, etc. Condition 2 was inspect each matrix for all five defects simultaneously. Condition 3 was inspect each matrix for “similar” characteristics (AB$ or 345 + 678). If inspection is “easy” (inspection for $, A or B), there is no difference in accuracy between inspection for one or multiple defects at a time but a considerable time penalty for inspecting for one defect at a time. If the inspection is “difficult” (inspection for 345 or 678), inspection for one defect at a time gave 15% less errors with a 22% increase in time.