Injuries in electric and gas utilities averaged 175 days of disability per case, a reduction of 5 days from the previous year. The severity rate, however, was relatively low (1.5), reflecting the low frequency rate (8.7). Both rates were improved somewhat from their 1953 levels. Companies providing gas service exclusively continued to have a better record (severity rate of 0.9 and 77 days of disability per case) than those providing electricity exclusively (severity rate of 2.0 and 251 days of disability per case) or those providing

both gas and electricity (severity rate of 1.3 and 168 days of disability per case). Police and fire departments had severity rates of 2.8 and 2.9, respectively, a slight improvement over the previous year.

Stevedoring had the highest severity rate-17.2 days of disability per 1,000 hours worked-of any industry included in the Bureau's survey.

-JOHN C. MACHISAK Division of Industrial Hazards

Safety Code for Atomic

Radiation in New York Industries

1

INCREASING industrial application of developments in the field of atomic energy have underscored the need for establishing safety programs to combat this relatively new but growing source of work hazards. A pioneering step in this direction occurred on December 15, 1955, when safety regulations designed to protect New York State workers from on-the-job hazards of atomic energy and other radiation went into effect. The new regulations are in conformity with proposed Federal Atomic Energy Commission standards and constitute reportedly the first comprehensive safety code in this field. They will be enforced by the safety and industrial hygiene staffs of the New York State Department of Labor.

The adoption of the code by New York State's Board of Standards and Appeals is the culmination of a 2-year study by a 26-man State Labor Department advisory committee, composed of labor, management, medical, scientific, and government representatives. The code applies to the entire field of atomic radiation, including the industrial use of isotopes. An estimated 150,000 New York workers who are employed in industries where exposure to the effects of radiation is possible will be protected under the new regulations. The code complements recently adopted radiation safety regulations of the New York State Health Department providing for the pro

tection of personnel in hospitals, dental offices, and similar establishments.

Significant requirements of the code are contained in provisions concerning registration, control of exposure, radiation dose limits, installation surveys, recordkeeping, personnel monitoring, caution labels, and signs. Among them are:

All installations and mobile services must be registered to enable the Labor Department to know the location, type, degree of hazard, and ownership of every radiation source in the State.

Each installation must have a radiation safety supervisor and a radiation safety officer who is designated by the owner. Workers exposed to radiation must be trained by a supervisor and be completely informed of hazards in installations. Minors under 18 will not be permitted to work in areas of possible hazard.

The owner of an installation is given the option of two methods of determining dose limits on a weekly basis or on a quarter-year dose-limit basis. When an employee is exposed to greater than one-tenth of the specified limits, the employer shall report the fact to the proper authority. Any employee who receives 25 percent or more of the radiation-dose limit must be supplied with and must use appropriate personnel monitoring equipment.

The radiation safety officer will be required to make a survey evaluating the hazard when conditions in the installation change or more often. Proper detection and measuring instruments must be readily available.

The new code also sets up a requirement for the posting of precautionary signs or labeling in radiation areas. These must contain the standard radiation symbol, which is specified, and appropriate cautionary wording. Permissible exposure limits are based on those provided in the proposed AEC regulation.

1 Industrial Code Rule No. 38.

Indexes of Output per Man-Hour and Unit Man-Hours in Manufacturing*

EDITOR'S NOTE.-The following technical note, and the article which appears on page 1 of this issue, were condensed from the report on Trends in Output per Man-hour and Manhours per Unit of Output-Manufacturing, 1939-53, recently issued by the Department of Labor's Bureau of Labor Statistics. A fuller discussion of the concepts and formulation of the physical output and net output indexes presented in the article was also published in a technical note on the Relationships Between Productivity Measures, which appeared in the May 1954 Monthly Labor Review (p. 552).

Physical Output Indexes

INDEXES of output per man-hour (and the reciprocal man-hours per unit of output) based on physical production data measure the relationship between physical production and man-hours worked by production and related workers.2 In concept, the goal is the measurement of physical production per man-hour, excluding the effects of variation in the relative importance of products or industries.

The new Bureau of Labor Statistics indexes of output per man-hour (unit man-hours) in manufacturing are aggregates of indexes for individual industries, which were derived by preparing separate indexes of production and man-hours and then dividing one by the other. The industry productivity measures were combined in two ways: (1) with fixed (base year) man-hour weights, and (2) with changing (current year) man-hour weights. In the latter, the weighting pattern of each successive current year is used with current year and base year data. Inasmuch as only the given year and the base year figures are comparable, indexes for adjacent years may not be validly compared. Imputations were made for missing

Production Indexes. The data used in constructing the industry production indexes were obtained from a number of public and private agencies. The Bureau of the Census of the U. S. Department of Commerce was the most important source: its Facts for Industry series provided data for approximately 50 of the indexes in the years 1947 and 1949-53, and BLS drew heavily upon the 1939 and 1947 censuses of manufactures in constructing the benchmark indexes. Other public sources were the Department of Agriculture, the Bureau of Mines of the Department of the Interior, the Tariff Commission, and the Internal Revenue Service. Data also came from a number of industrial trade associations and trade publications.

Prepared by Allan D. Searle and Jack Alterman in the Bureau's Division of Productivity and Technological Developments.

1 BLS Report No. 100, 1955. (Single copies are furnished without cost upon request to the Bureau's Washington or regional offices.)

The term "production and related workers" covers working foremen and all nonsupervisory workers, including leadmen and trainees, "engaged in fabricating, processing, assembling, inspection, receiving, storage, handling, packing, warehousing, shipping, maintenance, repair, janitorial, watchmen services, product development, recordkeeping, auxiliary production for plant's own use (e. g., power plant operations), and other services closely associated with the above production activities of establishments." The term thus includes some indirect as well as direct plant labor.

• Standard Industrial Classification Manual, Vol. I, Manufacturing Industries, Bureau of the Budget, November 1945.

In many cases, inclusion of quantity statistics for all the items produced in an industry was not possible or necessary. The Bureau, however, used as much product detail as the availability of output data and weights permitted. In all cases, the value of the output represented in the index constituted at least 50 percent of the total value of the industry's products.

The choice of the unit in which production is measured was limited by the way in which the data were reported. Where a choice exists-as in the textile industry, where the output of cloth can be measured in linear yards, square yards, or pounds the Bureau tried to select the measuring unit most nearly related (i. e., proportional) to the man-hours used in its production.

To convert the different units to a common basis, the number of units of each product were combined by means of weights. Unit man-hour weights are preferable for an index designed to measure physical output per man-hour, in order to eliminate the influence of shifts in the relative importance of products. But unit man-hour data were available on an individual product basis in only a few large industries; where they were lacking, data on unit labor costs, unit value added, or unit value, in that order of preference, were used. Tests were made to determine to what degree the weights other than man-hours were proportional to, and therefore representative of, labor requirements. The types and importance of weights used in combining product data are shown in the following tabulation:

Limitations of Production Data. For some industries the only available output data were shipments of finished goods, rather than production. To the degree that manufacturers' inventories change from year to year, shipments data would not be comparable with data on production-worker man-hours. Therefore, adjustments for finished goods inventories were made (except in 1949, for which needed inventory data were lacking) for 72 of the 79 industries in which output was measured by means of deflated value of shipments or physical quantity of shipments data.

The basic production data did not include the output of purely military products by industries normally producing civilian goods. The Bureau, in conjunction with the Federal Reserve Board, developed special tabulations (based on Census data) for use in making adjustments to correct for the downward bias caused by the increase in military production which took place in 1951-53 in the industry groups affected, i. e., metalworking and clothing.

Production data were rarely available for the entire output of an industry. Varying proportions of secondary production were unreported; furthermore, some of the production figures were on a "wherever made" basis-i. e., included quantities made as secondary products in other industries. Because man-hours are reported on an industry basis, however, the coverage of the production and man-hour indexes might not match. For the years 1939 and 1947, the BLS made adjustments to correct for changing coverage of the production data in a number of industries where such correction seemed warranted. These adjustments were based on the 1939 and 1947 ratios of the value of identical items in the index to the total value of the industry's products.

This adjustment technique involves the assumption that price movements of items not covered move in the same way as prices of included items. Rather than make this assumption for all products the Bureau assumed that prices of products nor mally classified in an industry generally move together, even though some of them may be made in other industries. This assumption was not uniformly made, however, with respect to the secondary products, for which price movement may follow those of the industry to which they are primary rather than those of the industry in which they are made.

Accordingly, the following standards were established for acceptance or rejection of the coverage adjustment for the 1939-47 period.

1. If the change in coverage of the production data was less than 5 percent, no adjustment was made. 2. If the adjustment was between 5 percent and 20 percent, it was accepted if caused principally by changes in the proportion of the value of primary products made outside the industry. If the change in coverage was principally due to changes in proportions of secondary production, no adjustment was made.

3. The few cases in which the adjustment amounted to 20 percent or more were subjected to special attention. Information on price movements and other knowledge was used to determine whether the index should be adjusted, combined with data for other industries, remain unadjusted, or abandoned.

New products often were not included in the production indexes until they became important enough to be reported to the Bureau of the Census. Sometimes new products were included as a part of another product class, until they became important enough for separate reporting, when they were "linked" into the index. When the Bureau of Labor Statistics had information on new products, it added them to the composite of output, attempting to determine when they were first manufactured and treating them as "zero" for the years preceding.

In the Bureau's production index, as in other measures of production, such intangibles as quality change cannot be taken into account. To do so would involve assigning values to consumer preference and utility. Since, on the whole, the quality of goods is improving and many quality improvements require additional man-hours but are not reflected in production measures, the indexes understate gains in productivity. (In exceptional periods such as wartime, an opposite bias probably occurs.)

Another data problem which may affect the physical output indexes is that of plant integration. As plants become more integrated, that is, produce more of the components used in the manufacture of the final product, the volume of items reported as production tends to decline relative to

A comparison of indexes for 1939 reveals that the effect of the coverage f adjustment was not substantial for total manufacturing during the period overed. Actually, production indexes for total manufacturing based on combinations of the lower of the adjusted or unadjusted industry indexes and combinations of the higher of the two industry measures were 58.5 and 503 (1947-100), respectively.

man-hours reported. On the other hand, as plants specialize, i.e., purchase more components, such as subassemblies, from other establishments, the volume of items reported as production increases relative to man-hours. However, because integration and specialization are occurring among all industries, the net effect on the total manufacturing sector is probably small.

Certain rigidities imposed by industrial classification also affect the measures. As plants shift major production from one type of goods to another, they may be reclassified from one industry to another, and thus affect the level of output per man-hour in the industries involved. This limitation is also considered to be relatively insignificant for the total manufacturing sector.

Net Output Indexes

The concept of "net output" relates to the value added in the course of the manufacturing process and is an indicator of the volume of work done. For a given year, net output is equal to the value of goods sold by establishments in an industry or transferred to other plants of the same company plus (or minus) the net change in the value of finished goods and goods-in-process inventories (i.e., gross output) less the value of purchased goods and business services consumed in production. Thus, the new BLS indexes of output per man-hour (or man-hours per unit of output) in manufacturing computed from the net output aggregates adjusted for price change are affected by changes not only in the physical volume of gross output but also in the quantity of materials consumed. The BLS net output measure is close to but not identical with the value added concept of Census data. The latter are not adjusted for changes in inventories of finished goods and goods in process and are in current dollars, whereas the BLS measure has been adjusted to eliminate the effect of price change. The BLS index of net output per man-hour is comparable in concept to measures of private gross national product per man-hour, because the gross national product can be considered as the aggregate of value added by all industries in the economy. Both measures are affected by shifts between industries and changes in the proportion of materials to output.

The Bureau prepared two types of manufacturing net output indexes: (1) an index of net output

in base year (1947) prices, (2) an index of net output in current year prices.

The former series was obtained by first dividing the dollar value of production (shipments plus changes in inventories) and cost of materials for 1949 through 1953 by appropriate price indexes for individual industries and summing the deflated values. The annual net output (in constant dollars) for all manufacturing industries combined was then derived as the difference between total production and costs of materials. Finally, the index was based on the ratio of the given year net output to the 1947 total.

The second index, with given year price weights, was constructed by multiplying the value of production and the cost of materials in 1947 by appropriate price indexes for each of the years 1939 and 1949 through 1953. The net output total for each year (i. e., the difference between the value of production and the cost of materials) in given year prices, was then divided by the 1947 total in prices of the respective year to obtain the index. As only the given year and base year figures are comparable, indexes for adjacent years may not be validly compared.

The net output per man-hour indexes for manufacturing as a whole were obtained by dividing net output annual indexes by corresponding manhour series. For the reciprocal indexes of manhours per unit of output, of course, the man-hour series were divided by the net output indexes.

Measuring Net Factory Output. In estimating net manufacturing output for 1947-53, the BLS utilized the data on dollar value of shipments, finished goods and goods-in-process inventories, and cost of materials for individual industries from the 1947 Census of Manufactures and the Annual Surveys of Manufactures for 1949 to 1953. Published data from these sources were supplemented by unpublished tabulations and by special estimates. Totals for manufacturing cover virtually all of the approximately 450 Census industries. For 1939, data on value of production and cost of materials were obtained from the 1939 Census of Manufactures.

The Census industry estimates cover the total activity of establishments classified in the industry. Data on value of shipments and costs of materials therefore relate both to primary products of the

industry and to secondary products or items made primarily in other industries.

To correct annual 1947-53 data on value of shipments for price changes, indexes were specially constructed from the BLS wholesale commodity price series. Price series for 1,800 specific products were classified by producing industry and combined into industry indexes. The commodities represented in the resulting industry index were those primary to the industry. Owing to the lack of readily available data on price movements of secondary products, prices of these were assumed to follow those for primary products. The weights used in combining product price indexes were based on value of shipments data from the 1947 Census of Manufactures. For the 1939-47 period, implicit price indexes were derived from the Census value of output and the detailed industry production indexes developed by the Bureau of the Census and the Federal Reserve Board.

An index of the prices paid for goods consumed by each industry was required to correct the annual value of materials consumed for price changes. The basis for constructing these cost deflators was the BLS interindustry chart showing the particular industries from which each industry purchased goods and services in 1947 and the actual value of such purchases. For the period 1947-52, cost deflators were constructed for each industry by combining the price indexes for supplying industries, derived in the manner described in the preceding paragraph, with weights based on the value of purchases in 1947 by the consuming industry. For 1939 and 1953, the cost of materials was deflated at the total manufacturing level, rather than for individual industries. These adjustments

were based on a special tabulation of the value of purchases by all manufacturing industries from each producing industry.

To derive estimates more consistent with the net output concept and to improve their accuracy several important adjustments of the data were made. First, estimates of the value of shipments (in constant dollars) were adjusted to include the

As a test, two price indexes were prepared-one in which individua price series were combined with total value of industry output (primary and secondary) as weights and the other, in which the weights were value o primary product wherever made. The two indexes were practically identical See summary tables (three tables, 200 sector detail), Bureau of Labor Statistics, October 1952 (16 sections); see also W. Duane Evans and Marvin Hoffenberg, Inter industry Relations Study for 1947 (in Review of Econom ics and Statistics, Cambridge, Mass., May 1952, pp. 97-142).