Subject Headings Decision Table:
Map subjects: | Existing headings: | Headings used: | |
a | A, B | A, B | A, B |
b | A, B | A, B, Z (Z = A + B) | Z not A, B, Z |
c | A, B | A, B, Y (Y = A + B + ...) | A, B unless the extra scope in Y is so little as to be considered negligible |
d | A, B, C | A, B, C, X (X = A + B + C) | X |
e | A, B, C | A, B, C, Q (Q = A + B + C + ...) | A, B, C if the extra scope in Q is considerable Q if the extra scope is small |
f | A, B, C, D | A, B, C, D, R (R = A + B + C + D + ...) | R |
g | A, B, C, D | A, B, C, D, V (V = A + B + C) | V, D |
Note the differences between e and f. Three distinct subjects in a work usually receive the broader subject heading, unless the heading is very much broader than the combination of the 3 individual headings. Four subjects always receive the broader subject heading, regardless of the extra scope.