GENERAL

Content. This report presents statistics, by city blocks, on characteristics enumerated in the Census of Housing, taken as of April 1, 1960. The housing unit is the reporting unit for this report.

Statistics by blocks are published for each city or urban place which had a population of 50,000 or more in 1950 or in an interim census prior to 1960, and also had a population of 50,000 or more in 1960. In addition, a number of localities were included in the city block program through an agreement whereby the local government furnished satisfactory block maps and paid the Bureau of the Census for the incremental cost of collecting and publishing the information. Reports differing only in details are issued for the cities in Puerto Rico.

The information presented in this report represents a modification of the block statistics programs of the 1950 and 1940 Censuses of Housing. The 1960 program provides the following information for each block: Total population, the number of housing units classified by condition and plumbing, tenure of occupied units, average value and average number of rooms for owner occupied units, average contract rent and average number of rooms for renter occupied units, number of units occupied by nonwhites, and number of units with 1.01 or more persons per room. All of the items were enumerated and tabulated on a 100-percent basis for the statistics in this report.

The 1960 Census contained several innovations. One of them was the use of an advance census report form which was sent to each household in the United States, with the request that the household members themselves complete it prior to the enumerator's visit. Another innovation was the extensive use of the electronic computer and related equipment to process the data and produce the final tables. These innovations were designed primarily to improve the quality of the data and to permit early publication; at the same time, they have introduced an element of difference between the 1960 statistics and those of earlier

censuses.

Changes were made also in the definitions of some of the major concepts. They were made in order to improve the usefulness of the data although it was recognized that comparability with previous censuses would be affected. Innovations and changes are discussed in later sections of this report and in more detail in the United States Summary, Volume I of the Housing Reports.

Description of tables.-This report contains two tables: Table 1 summarizes the statistics for the city, urban place, or locality as specified in the table; table 2 contains the statistics for individual blocks, as well as totals by tract or block numbering area where appropriate.

To avoid disclosure of information for individual units, some of the data were suppressed in table 2. Specifically, if there were four or fewer total housing units in the block, the items suppressed were condition and plumbing, total owner occupied, total renter occupied, occupied by nonwhite, and 1.01 or more persons per room. If there were four or fewer owner or renter occupied units, average number of rooms for the respective tenure group was suppressed. Similarly, average value and average rent were

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suppressed if there were four or fewer units of the type for which value and rent were tabulated. All units, however, are included in the totals for the city or locality and in the totals for the census tract or block numbering area. Leaders (---) in a data column in table 2 indicate that either there were no housing units in the category or that the data were suppressed.

Block identification, total population, and total housing units are shown in table 2 for every block that contained living quarters. For some blocks, the table shows total population but no housing units because all the people lived in group quarters; while for other blocks, the table shows housing units but no population because all the units were vacant. Blocks with no living quarters are shown on the map but do not appear in table 2. Maps and block identification. The map included in this report identifies the boundaries of the city, urban place, or locality for which the block statistics are provided. The map also identifies the location and number of each block and, where appropriate, the boundary and number of each census tract or block numbering area. The total number of blocks identified on the map, including blocks with no living quarters, is given in the note following table 1.

A block is usually a well-defined rectangular piece of land bounded by streets or roads. However, it may be irregular in shape or bounded by railroad tracks, streams, or other features. The block is the specific numbered area as shown on the map.

Census tracts are small areas into which large cities and metropolitan areas have been divided for statistical purposes. Tract boundaries were established cooperatively by a local committee and the Bureau of the Census, and were generally designed to achieve some uniformity of population characteristics, economic status, and living conditions. Initially, the average

tract had about 4,000 residents. Tract boundaries were established with the intention of being maintained over a long time so that comparisons may be made from census to census. If tract boundaries extend beyond the area included in this report, statistics are shown for that portion of the tract inside the area. In untracted places, block numbering areas are generally used. Block numbering areas are established by arbitrarily dividing the city along major streets, railroads, or other physical boundaries to facilitate numbering the blocks in groups of fewer than 1,000. The boundaries of block numbering areas have no statistical significance but are merely for convenience in mapping and tabulating.

In numbering the blocks, a separate series was used for each census tract or block numbering area. Thus, the location of each block for which data are presented in table 2 is determined by referring both to the block number and the census tract or block area number.

In smaller localities where there were neither census tracts nor block numbering areas, the blocks were numbered in one series within the locality as a whole.

In some cases, a city or other political boundary divides a block. The data shown are for that part of the block represented by the land area as bounded and numbered on the block map. Comparability with the 1950 Census of Housing. In the 1950 Census of Housing, reports entitled "Block Statistics" were issued for the 209 cities which, in 1940 or in an interim census

prior to 1950, had a population of 50,000 or more. The program was restricted to cities in conterminous United States, that is, the United States exclusive of Alaska and Hawaii.

The 1960 block program reflects changes and additions of items compared with the 1950 program, although the subjects covered in both programs are substantially similar. The changes that were made reflect the needs expressed by users of block data. For example, categories on condition and plumbing were expanded considerably to conform with needs for data to plan urban renewal programs. Total population and average number of rooms have been added, and the category 1.01 or more persons per room has been substituted for 1.51 or more. Two categories of vacant units, which were included in the 1950 report, are not shown in 1960.

Below is a list of the 1960 items published by blocks and the equivalent or comparable 1950 items (table 2 in the 1960 report and table 3 in the 1950 report). As noted previously, changes in categories, concepts, and procedures may affect comparisons between the 1960 and 1950 statistics.

Wherever possible, the block numbers in 1960 remained the same as in 1950 for blocks whose boundaries did not change. However, changes in block numbers and the assignment of new numbers have been necessary for blocks which have been divided or newly created since the 1950 Census, for blocks in tracts which have had their boundaries changed, and for blocks in places or areas newly tracted in 1960.

Housing data from other censuses.-The 1940 Census of Housing was the first to provide housing statistics by blocks. Reports entitled "Block Statistics" were issued as supplements to the first series of housing bulletins. These supplements consisted of separate reports for each of the 191 cities in conterminous United States which had 50,000 inhabitants or more in 1930.

Availability of unpublished data.-There are no unpublished data from the 1960 Census for blocks. All the information that was tabulated is included in this report. However, some unpublished data are available on request for other small areas such as enumeration districts, census tracts, and minor civil divisions.

DEFINITIONS AND EXPLANATIONS

Interpretation of definitions.-Some of the definitions used in 1960 differ from those used in 1950, as indicated below. These changes were made after consultation with users of census data in order to improve the statistics even though it was recognized that comparability would be affected.

The definitions and explanations should be interpreted in the context of the 1960 Census, which employed a combination of self-enumeration, direct interview, and enumerator observation.

housing units was obtained by the enumerator as part of the procedure to secure complete coverage of all living quarters. Further, condition of a unit was always determined by enumerator observation. The remaining items were completed by selfenumeration, or by direct interview when the household member did not complete the form. For items on the self-enumeration form (the Advance Census Report), the respondent had the explanations and instructions printed on the form.

The definitions below are consistent with the instructions given to the enumerator for items he was to complete himself and for all items which were not completed by the respondent on the self-enumeration form. As in all surveys, there were some failures to execute the instructions exactly. Through the forms distributed to households, the respondents' attention was drawn to some of the explanations of the questions more uniformly than might have been the case in direct interviews. Nevertheless, it was not feasible to give the full instructions to the respondents, and some of their errors have undoubtedly gone undetected.

Total population.-The total population is the count of all persons living in the block. When the population includes persons living in group quarters, the figure is preceded by one asterisk if the proportion in group quarters is less than 10 percent of the total population, and by two asterisks if the proportion is 10 percent or more. If the total population includes persons in group quarters, the count cannot be used in the computation of the average number of persons in occupied housing units.

For places for which the total population includes crews of vessels, the population obtained as the sum of the counts by blocks is less than the total population shown in other census reports. Crews of vessels were not allocated to blocks and, therefore, were excluded from the block tabulations.

Living quarters.-Living quarters were divided into housing units and group quarters. The classification of occupied living quarters as housing units or group quarters was based on information supplied by household members on the Advance Census Report and questions asked by the enumerator where necessary. Delineation of vacant quarters was based partly on the enumerator's observation and partly on information obtained from landlords and neighbors.

A house, an apartment or other group of rooms, or a single room is regarded as a housing unit when it is occupied or intended for occupancy as separate living quarters, that is, when the occupants do not live and eat with any other persons in the structure and when there is either (1) direct access from the outside or through a common hall or (2) a kitchen or cooking equipment for the exclusive use of the occupants.

Quarters in which the occupants do not have separate living arrangements are classified as group quarters. They are located most frequently in institutions, hospitals, nurses' homes, rooming and boarding houses, military and other types of barracks, college dormitories, fraternity and sorority houses, convents, and monasteries. Group quarters are also located in a house or apartment in which the living quarters are shared by the person in charge and five or more persons unrelated to him. Group quarters are not included in the housing inventory, although the count of persons living in them is included in the total population in table 2.

The inventory of housing units includes vacant as well as occupied units. Newly constructed vacant units were included in the inventory if construction had reached the point that all the exterior windows and doors were installed and the final usable floors were in place. Dilapidated vacant units were included provided they were still usable as living quarters; they were excluded if they were in the process of being demolished or if there was positive evidence that they were to be demolished. Trailers, tents, boats, and railroad cars were included in the