Vacant units available group is limited to units

for sale

only. --This for sale only; it excludes units "for rent or sale." If a unit was located in a multiunit structure which was for sale as an entire structure, and if the unit was not for rent, it was reported as "held off market." However, if the individual unit was intended to be occupied by the new owner it was reported as for sale.

Vacant units rented or sold.--This group consists of year-round vacant units in sound or deteriorating condition which have been rented or sold but the new renters or owners have not moved in as of the day of enumeration. In the 1950 statistics, such units are shown in combination with year-round not dilapidated vacant units held off the market.

Vacant units held off the market. -- Included

in this category are year-round units in sound or deteriorating condition which were vacant for reasons other than those mentioned above: For example, held for occupancy of a caretaker, janitor, and the like; held for settlement of estate; held for personal reasons of the owner; and temporarily occupied by persons who have a usual place of residence elsewhere. In the 1950 statistics, such units are shown in combination with year-round not dilapidated vacant units, rented or sold, as "nonseasonal not dilapidated, not for rent or sale" units.

Rental vacancy rate.--The percentage relationship of the vacant units available for rent to the total rental inventory is termed the rental vacancy rate. It is computed by dividing the number of vacant units available for rent by the total rental units. The total rental units consist of the renter-occupied units, vacant units rented but not yet occupied at the time of enumeration, and the vacant units available for rent. Vacant units that are dilapidated, seasonal, or held off the market are excluded.

The total

Homeowner vacancy rate. --The percentage relationship between the vacant units available for sale and the total homeowner inventory is termed the homeowner vacancy rate. It is computed by dividing the number of vacant units available for sale by the total home owner units. homeowner units consist of the owner-occupied units, vacant units sold and awaiting occupancy, and the vacant units available for sale. Vacant units that are dilapidated, seasonal, or held off the market are excluded.

Duration of vacancy.--The length of time a housing unit was vacant was computed from the day

the unit became vacant until the day of enumeration. It should be noted that the time period is not the total time a unit remains unoccupied nor the time a unit has been in a particular vacancy status, but it is the duration of vacancy up to the day of enumeration. For newly constructed units, it represents the time period since the date when the unit was considered a vacancy, that is, when construction had reached the point that all exterior windows and doors were installed and final usable floors were in place.

The time intervals used in the tables represent full months, calculated from a date in the month to the same date the following months. For example, if the unit became vacant on Oct. 29 and was still vacant on the day of enumeration, Dec. 20, the time reported would be "1 up to 2 months," meaning that the unit had been vacant for more than one month but less than two months. Or if the unit became vacant on Nov. 25 and was still vacant on Dec. 20, the time reported would be "less than 1 month."

CONDITION AND PLUMBING FACILITIES

Condition of housing unit. --The structural condition of a housing unit is considered one of the measures of the quality of housing. Beginning the first quarter 1961, the condition of vacant housing units was measured according to the concept used in the 1960 Census. Three categories were used: Sound, deteriorating, and dilapidated. In preceding quarters and in 1950, two categories were used: Not dilapidated or dilapidated. The category "Sound or deteriorating" is assumed to be equivalent to the category "Not dilapidated."

Sound housing has no defects, or only slight defects which are normally corrected during the course of regular maintenance. Examples of slight defects include: Lack of paint; slight damage to porch or steps; small cracks in walls, plaster, or chimney; broken gutters or downspouts; slight wear on floors or doorsills.

Deteriorating housing needs more repair than would be provided in the course of regular maintenance. It has one or more defects of an intermediate nature that must be corrected if the unit is to continue to provide safe and adequate shelter. Examples of such defects include: Shaky or unsafe porch or steps; holes, open cracks or missing materials over a small area of the floors, walls, or roof; rotted window sills or frames; deep wear on floors or doorsills; broken or loose stair treads or missing balusters. Such defects are signs of neglect which lead to serious structural damage if not corrected.

Dilapidated housing does not provide safe and adequate shelter. It has one or more critical defects; or has a combination of intermediate defects in sufficient number to require extensive repair or rebuilding; or is of inadequate original construction. Critical defects are those which indicate continued neglect and serious damage to the structure. Examples of critical defects include: Holes, open cracks or missing materials over a large area of the floors, walls, roof, or other parts of the structure; sagging floors, walls, or roof; damage by storm or fire. Inadequate original construction includes structures built of makeshift materials and inadequately converted cellars, sheds, or garages not originally intended as living quarters.

The enumerator determined the condition of the housing unit on the basis of his own observation. He was instructed to appraise the condition of units uniformly, regardless of the neighborhood. The enumerator was provided with detailed written instructions and with pictures illustrating the concepts "sound," "deteriorating," "dilapidated."

and

Although the enumerator was provided with

detailed oral and written instructions and with visual aids, it was not possible to eliminate completely the element of judgment in the enumeration of this item. It is possible that some enumerators obtained too large or too small a count of dilapidated units. However, with the large number of enumerators involved, it is likely that such deviations tend to be offsetting.

Plumbing facilities.--Housing units "with all facilities" consist of those which have both a flush toilet and a bathtub or shower inside the structure for the exclusive use of the intended occupants, and hot running water.

Units "lacking facilities" consist of those which lack one or more of the plumbing facilities or which lack exclusive use of these facilities. For example, included as "lacking facilities" would be a downstairs apartment with hot running water but whose occupants would share the bathroom with the occupants of the upstairs apartment.

Facilities were considered "inside the structure" if they were located within the housing unit or elsewhere in the structure. Facilities are for exclusive use if only the intended occupants this one housing unit would use them.

of

A housing unit was considered as having hot running water whether it was available the year round or only part of the time. For example, hot running water may be available only during the heating season or at various times during the week.

STRUCTURAL CHARACTERISTICS

Number of

en

rooms.--All rooms which are to be used, or are suitable for use, as living quarters were counted in determining the number of rooms in the housing unit. Included are kitchens, bedrooms, dining rooms, living rooms, and permanently closed sunporches of substantial size; and finished basement or attic rooms, recreation rooms, or other rooms suitable for use as living quarters. A kitchenette or half-room which is partitioned off from floor to ceiling was counted as a separate room, but a combined kitchenette and dinette separated only by shelves or cabinets was counted as only one room. Not counted as rooms were bathrooms, strip or pullman kitchens, halls or foyers, alcoves, pantries, laundries, closets or storage space, and unfinished basement or attic rooms not suitable for living quarters.

The median number of rooms is the theoretical value which divides the housing units equally, one-half having more rooms and one-half having fewer rooms than the median. In the computation of the median, a continuous distribution was assumed. For example, when the median was in the 3-room group, the lower and upper limits were assumed to be 2.5 and 3.5, respectively. Tenths were used in the computation of the median to permit comparisons.

Number of bedrooms.--Only rooms intended primarily to be slept in were counted as bedrooms. A bed-living room or a den intended primarily for purposes other than sleeping was not counted as a bedroom. A 1-room apartment, therefore, was reported as having no bedroom. Also, space which could be made into bedrooms (the upper floor of a 1-story house, for example) was not counted as a bedroom unless it was finished off and suitable for use as living quarters.

Number of housing units in structure.--A structure either stands by itself or has vertical walls dividing it from all other structures. The count of housing units in a structure is the total number of units in the structure, including both occupied and vacant units. A structure may be detached, attached, or semidetached. A detached structure has open space on all four sides; an attached structure is one of a row of three or more adjoining structures, or is a structure attached to a nonresidential structure; while a semidetached structure is one of two adjoining residential structures, each with open space on the remaining three sides. In apartment developments, each building with open space on all sides is considered a separate structure.

The statistics reflect the number of vacant housing units classified by the number of housing units in the structure in which they are located, rather than the number of residential structures that contain vacant units.

In the quarterly surveys, data were obtained on the number of housing units in the structure, regardless of the type of structure (detached, attached, or semidetached) in which the unit was located.

Year structure built.--"Year built" refers to the date the original construction of the structure was completed, not to any later remodeling, addition, or conversion. The figures on the number of units built during a given period relate to the number of units in existence at the time of enumeration. The figures reflect the number of units constructed during a given period plus the number created by conversions in structures originally built during that period, minus the number lost in structures built during the period. Losses occur through demolition, fire, flood, disaster; change to nonresidential use; or merger to fewer housing units.

Data on year built are more susceptible to errors of response and nonreporting than data on many of the other items. In most cases, the information was given according to memory or estimates of the occupants of the structure or of other persons who had lived in the neighborhood a long time.

Monthly rent.--The monthly rent is the amount asked for the unit at the time of enumeration, regardless of whether it is to include furniture, heating fuel, electricity, cooking fuel, water, or other services. If the amount of rent were to vary during the year, the rent reported was the monthly amount asked at the time of enumeration. As in the 1960 Census, the statistics in this report are for all vacant rental units in urban areas and those in rural areas which are located on places of less than 10 acres; thus rural vacancies on places of 10 acres or more are excluded. The statistics in the reports for 1960 or earlier exclude rental vacancies in rural areas which were classified as farm by the 1950 definition (the classification depending on the reply to the question, "Is this house on a farm or ranch?"). Data for such units are excluded because of the difficulty of separating the rental for the housing unit from the rental for the land.

The median monthly rent is the rent which divides the series into two equal parts, one-half of the units with rents higher than the median and the other half with rents lower than the median. In the computation of the median, a continuous distribution was assumed; and the limits of the

class intervals were assumed to stand at the midpoints of the $1 interval between the end of one of the rent groups and the beginning of the next. For example, the limits of the interval designated $30 to $39 were assumed to be $29.50 and $39.50.

Inclusion of utilities in rent.--The utilities included in the inquiry were heat, light, cooking fuel, and water. The statistics reflect whether all or not all of these utilities are provided for in the amount of rent asked at the time of enumeration, not what could be provided for more or less rent. Data on the inclusion of utilities are limited to the same units as those for which rent is reported.

Sale price of 1-housing unit structures.--The sale price is the amount asked for the property, including the structure and its land. Statistics on sale price for this report are limited to units in 1-housing unit structures, without business, and with only one housing unit included in the property. As in the 1960 Census, the statistics in this report are for all vacant homeowner units in urban areas and those in rural areas which are located on places of less than 10 acres; thus rural vacancies on places of 10 acres or more are excluded. The statistics in the reports for 1960 or earlier exclude homeowner vacancies in rural areas which were classified as farm by the 1950 definition (the classification depending on the reply to the question, "Is this house on a farm or ranch?"). Data for such units are excluded because they would reflect varying amounts for land, business uses, or for more than one housing unit on the property.

The median sale price is the amount which divides the series into two equal parts, one-half of the units with prices higher than the median and the other half with prices lower than the median. The median was computed on the basis of more detailed tabulation groups than are shown in the and was rounded to the nearest hundred

tables dollars.

SOURCE AND RELIABILITY OF DATA

The Housing Vacancy Survey provides, on a quarterly basis, national and regional estimates on the size of the vacant housing inventory in relation to the rental and homeowner inventories as well as to the total housing inventory. The survey also provides information on the intended use of the unit, whether for year-round or seasonal occupancy, and on the structural condition. In addition, the results provide current information on the characteristics of vacant housing units offered

for rent or for sale only--their size, age and type of structure, how many months vacant, presence of plumbing facilities, and monthly rent or sale price asked.

The quarterly results are published in the Series H-111 reports. The first report issued covered April, May, and June, the three months comprising the second quarter 1955.

Source of data. --The estimates presented in this report are based on information collected from each housing unit identified as vacant in the monthly Current Population Survey of the Bureau of the Census. Data are collected monthly and combined to provide statistics for the three months comprising a quarter. The sample design and survey techniques for the Housing Vacancy Survey are the same as those used for the Current Population Survey.

The statistics presented for the quarter are averages for the three months comprising the quarter. The statistics presented for the year are averages for the four quarters of the year.

The current sample is spread over 357 areas comprising 701 counties and independent cities with coverage in each of the 50 States and the District of Columbia. A total of approximately 40,000 housing units and other living quarters are designated for each month's sample. Of this total, about 35,000 are occupied housing units; about 3,500 are vacant housing units; and the remainder are units which, at the time of enumeration, are determined to be unfit for human habitation, scheduled for demolition or already demolished, converted to nonresidential use, or are not living quarters within the scope of the survey. The sample currently in use was revised as of March 1963. The revision resulted in an increase in the number of sample areas with practically no change in the total number of sample units covered.1

From January 1960 to November 1961, the quarterly statistics shown in this report are based on a 333-area sample comprising 641 counties and independent cities with coverage in each of the 50 States and the District of Columbia. From December 1961 to February 1963, the sample was in process of transition from the 333-area sample used in December 1961 to the 357-area sample used beginning March 1963.

From May 1956 to December 1959, the sample was spread over 330 areas comprising 638 counties and independent cities with coverage in each of

the 48 States and the District of Columbia. A total of approximately 39,000 dwelling units and other living quarters were designated for the sample for each month. Of this total, about 34,000 were occupied dwelling units; 3,500 were vacant dwelling units; and the remainder were not living quarters within the scope of the survey.

The statistics covering the months March 1955 to April 1956 are based on a 230-area sample which comprised 453 counties and independent cities. A total of 24,000 to 26,000 dwelling units were designated for each month's sample. Of this total, about 21,000 to 23,000 were occupied dwelling units; 2,000 were vacant dwelling units; and the remainder were not considered living quarters within the scope of the survey.

The data shown for April 1960 and April 1950 in the individual reports are based on the returns of the decennial censuses of housing and represent the results of a complete enumeration.

on

Beginning in 1958, data were collected plumbing facilities of vacant housing units available for rent or for sale only. These data provided additional information on the quality of the vacant housing supply.

In 1960, the sample was expanded to include representation from Alaska and Hawaii. In addition, the housing definitions (except for condition of unit) and the definition of farm units were revised to conform with the definitions used for the 1960 Census of Housing. Prior to 1960, the data in this survey are based on the definitions used in the 1950 Census of Housing.

Beginning 1960, data on tenure of occupied housing units were collected on a continuing basis in one month of each quarter. (Between 1956 and 1960, estimates of tenure were projected from data collected in the 1950 Census of Housing and in the 1956 survey.)

Beginning 1961, the definitions on condition of vacant housing units were revised to reflect the three-way classification used in the 1960 Census. Also, beginning 1961, collection and processing procedures were changed; FOSDIC schedules were used for collecting the data and electronic equipment was used for processing the data.

In the second quarter 1962, the statistics for inside SMSA's and outside SMSA's were recoded

to reflect the 212 areas designated SMSA's at the time of the 1960 Census. Prior to 1962, the statistics relate to the 168 areas designated SMA's at the time of the 1950 Census.

Reliability of the estimates.--Since the quarterly statistics presented in this report are based on a sample, they are subject to sampling variability and may be expected to differ from results that would have been obtained from a complete count in which identical enumeration techniques were employed. The standard error is a measure of sampling variability. The chances are about 68 out

of 100 that the difference due to sampling variability between an estimate and the figure that would have been obtained from a complete enumeration is less than the standard error. The chances are about 95 out of 100 that the difference is less than twice the standard error and about 99 out of 100 that it is less than 2 times the standard error.

The standard errors of a few of the more important statistics are shown in table M. To illustrate: the rental vacancy rate for the United States for the quarter is estimated as 7.7 percent. As shown in table M, the standard error of this estimate is about 0.3 percent.

The chances

are, therefore, about 68 out of 100 that a complete enumeration would have yielded an estimate between 7.4 and 8.0 percent.

The annual average rates are subject to a smaller sampling variability than the quarterly rates. The variability for the annual average rate can be approximated by taking one-half of the standard error of the rate in table M.

Comparison of characteristics of vacancies for the fourth quarter 1965 with those for previous quarters (Series H-111, Nos. 1 to 42) reveals that many of the differences are small. A small difference, particularly when it is based on a small subclass of vacant housing units, should be interpreted with care. As can be seen from table M, the sampling variability in such cases may be large relative to the difference.

In addition to sampling variability, the data are subject to errors of response and biases due to nonreporting. Factors affecting accuracy of reporting are the respondent's knowledge of the facts and the enumerator's ability to obtain accurate information and classify the unit with respect to such items as condition, seasonal status, number of rooms, rent, sale price, and the like. The 1960 data also are subject to such possible biases and errors of response.