T HE geographic extent of the market has long been recognized as an important element of industry structure. For lack of systematic and direct measures, however, previous studies have relied either on rough classifications of geographical market size (local, regional or national) (Comanor and Wilson, 1967, p. 433; Kaysen and Turner, 1959, appendixes, pp. 283-285; Stigler, 1963, pp. 265-269 and 56-57) or on output dispersion indexes such as the number of states needed to account for 75 per cent of total shipments (Collins and Preston, 1968, 1969; Fuchs, 1962). This paper develops an alternative index of market size based on the Census of Transportation. Some attempts are made to evaluate various measures of market extent by comparisons with indexes of output dispersion and with an element of transport cost. It ends with a brief summary of the geographic market sizes of United States manufacturing industries.

SOME of the highest profit rates appear in industries that advertise heavily. These high earnings have been attributed to barriers to entry associated with product differentiation [2, 6]. A possible alternative explanation is that the treatment of long-lived advertising as current expenses leads firms that invest heavily in such intangibles to overstate their rates of return since their equity is understated [1, p. 153; 15, p. 167]. The same practice may result in the understatement of their dollar profits so that they pay less tax than other firms whose investments are all tangible. The purpose of this paper is to work out more precisely the overor under-statement of profit and rate of return involved in the expensing of advertising and to evaluate the mis-statement in practice.' Part I develops conceptually the conditions under which overor under-statements can be expected. Part II recomputes dollar profits and rates of return for a variety of industries, estimates the tax avoidance that results, and examines the relationship between recomputed profit rates and advertising. Part III contains a proposal for policy change.

ECONOMISTS have long attacked horizontal merger for its role in increasing concentration and defended it as a relatively painless means of attaining economies of scale and/ or inter-regional entry. This paper attempts to evaluate these divergent views using the experience of six large industries. In part I, the data and definitions used are explained. In part II, an attempt is made to measure the role of merger and of various other factors in concentration change. Part III examines the proportion of acquired capacity that is sub-optimal in scale, and part IV, the proportion that is inter-regional. Part V contains some brief conclusions.