making both controls necessary to achieve
the desired results (Widener, 2004). Milgrom and Roberts
(1995) illustrated analytically that control mechanisms can
be complementary, as an increase in the emphasis on
one control component increases the benefits gained from
increasing the emphasis on another control. Investigating
controls in combination is therefore important because a
control may add to, detract from, or multiply the effects of
another. A combination can also bring about equifinality, in
which different combinations of control practices produce
equivalent results (Anderson and Dekker, 2005).