The following table indicates the classifications to which the manufacturing industries have been assigned and the data used in analyses of prices and degree of concentration.

Under the column "Size code" the letters L, M, and S indicate large industries (L) employing 100,000 or more persons, medium industries (M) employing between 25,000 and 100,000 persons, and small industries (S) employing less than 25,000 persons.

The next column indicates the durability of the products of each industry. The basis for classification is that used in the report of the National Bureau of Economic Research Commodity Flow and Capital Formation. Nondurable or perishable products are those that, without marked change and retaining their essential physical identity, are ordinarily employed in their ultimate use less than 6 months. Semidurable products are those that, without marked change and retaining their essential physical identity are ordinarily employed in their ultimate use from 6 months to 3 years. Durable products are those that normally render successive services and are ordinarily employed in their ultimate use over a period longer than 3 years. The next column classifies industries into finished or semimanufactured categories. Products which move to the ultimate consumer with no further processing are classified as finished and those which are used as materials by other manufacturers are classified as semimanufactured.

The concentration index represents for each industry the proportion of the total value of product for the industry contributed by the largest four producers.

1 Appendix 8 was prepared by Grace W. Knott.

264

The value added ratios for 1929 and 1935 represent the ratio between value added by manufacture and value of product for the industry.

Under "Type of market," industries are classified into three groups: Those selling to a local market, those selling to a regional market, and those selling to a national market.

The column giving location determinant classifies industries into three groups: Those industries the location of which is largely determined by the location of the consumer, those which are situated close to the raw materials, and the remaining industries classified under "Other determinants."

Under "Type of industry" two categories are used: straight and mixed. Industries classified as straight are those in which each manufacturer as a rule engages in the production of all commodities covered by the industry classification. Industries in which the manufacturers confine themselves to the production of only part of the commodities included in the industry are classified as mixed.

The price ratios were computed from Bureau of Labor Statistics prices for 1929 and 1932. Prices of manufactured goods were assigned to the proper industry. Where more than one price item appeared for an industry, the Bureau of Labor Statistics weights were used for each item to derive a weighted average price for the industry.

Under reliability of price data notations of "Adequate," "Fair," and "Poor" are used to describe the adequacy of the price data insofar as they can be used to typify the prices of products of an entire Census industry.