Economists prefer to minimize cost. Test economics focuses on the relationship between testing cost and product quality. Costs include cost of ATE, cost test development (CAD tools, test vector generation, test programming) and the cost of DFT. Fixed and variable costs of material, equipment, labor, etc. are important

Benefit cost analysis: Benefits include income and saving in cost and time. Cost refers to the cost of labors, machinery, risk, energy, finance, etc. Both benefits and cost must be estimated for life time of product. When there is choice among products of same utility, B/C ratio provides criteria for comparison.

Rule of ten: If a chip fault is not caught by chip testing then finding the fault at PCB level costs ten times more than at the chip level. Similarly if a board fault is not caught by PCB testing then finding fault at system levels costs ten times more than at board levels. Some claimed that this must be renamed as rule of twenty since complexity of chip, board and system has increased a lot after the rule was first stated.