3.2. Definition of attributes of PD
The definition of the attributes was based on five criteria:
(a) the attributes should be, as far as possible, generalizable both
for safety and quality PD;
(b) the attributes should take into account the whole life-cycle of
the PD, ranging from its design process to its replacement;
(c) the attributes should be concerned with PD used in the manufacturing
of products, rather than being concerned with PD used
in other phases of the life-cycle of a product, such as its design
and use by end customers. It is worth noting that this criterion
is not contradictory with the previous one. While criterion (b)
states that the whole life-cycle of the PD should be taken into
account by the attributes, criterion (c) states that the attributes
should consider a specific stage of the life-cycle of the products
inspected by PD (i.e., the stage of manufacturing);
(d) the attributes should be consistent with the concept of pokayoke
presented in section 2 of this article (definition of pokayoke),
while recognizing that they are not necessarily fail-safe,
even though this is the ideal situation;
(e) the attributes should be grounded on a sound theoretical basis,
mostly drawn from the fields of human factors and LP.