When the final outcome is not readily observable and is difficult to quantify, one would expect
. the use of a (monthly) salary scheme, with workers having little incentive to shirk on quality,
although they may shirk on quantity. In this case,
since quality is a primary concern, the salary
system is more advantageous to the principal than
any other payment method. As noted earlier,
where marginal products of individual workers
are not easily separable, salary is invariably used
as the method of payment.