Two key issues concerning marketing functions are whether the necessary number of functions is being performed, and whether these functions are being performed in the most efficient manner. Because the functions add value as well as cost to products simply minimizing the function is not an acceptable goal. The rule is that additional functions and services should be performed until costs exceed the values of functions-a difficult point to determine in practice. It is important to determine when the shifting of a marketing function from one firm to another, or the combining of additional functions into one firm, is warranted. Some functions are most efficiently performed by specialized firms; others seem appropriately combined in multifunctional firms.

In agricultural production it is important for farmers to consider whether they should perform more or fewer of the agricultural marketing functions. There is no guarantee that profits will flow to those who assume additional marketing functions, even when functions are known to be profitable. Some managers can perform the functions more efficiently than others. Food retailers would probably make poor farmers, just as farmers may lack the skills and interest to manage a modern supermarket or a complex railroad network. The general trend in the food industry is toward combining additional marketing functions within a single firm. This is attributable to complementarities in marketing functions in raising profits and the desire for additional market power.