For each of the 15 attributes, the sources of evidence were established
(see Tables 1 and 2), thus seeking, to the extent possible, to
establish at least two sources per attribute. As to the sources that
involve interviews, the questions to be posed are related to the
actual wording of the attribute. For example, to assess attribute
BP1 (see Table 2), a representative of the design team should be
questioned about the reasons that led to setting up the poka-yoke
in that specific operation. From Tables 1 and 2, it is also possible to
draw up lists that compile all the sources of evidence of one and the
same type. For example, a specific list could be developed stating
all observations that should be carried out and another list could
state all documents that should be consulted.