Table 3 Basic operations in Boolean/fuzzy algebra and definitions of quality check instruments, according to [38]

*

Logical AND

+

Logical OR

Outcome in upper-case letters (Y)

Positive outcome (= acceptance)

Outcome in lower-case letters (y)

Negative outcome (= rejection)

Condition in upper-case letters (e.g. INTEREST)

Condition is present.

Condition in lower-case letters (e.g. interest)

Condition is absent.

Consistency of necessary or sufficient condition

Degree of data being in line with statement of necessity or sufficiency.

Coverage of necessary condition

Relevance measure of necessary condition; coverage within the set of all cases.

Raw coverage of sufficient conditions

Degree to which outcome is covered by a statement.

Unique coverage of sufficient conditions

Degree to which outcome is UNIQUELY covered by a statement.

Solution coverage

Degree to which outcome is covered by the all pathways/entire solution term.

Logical remainder

A possible logical combination without empirical evidence.

Conservative solution term

Solution term without assumption about logical remainders.