B. Collections of Information Employing Statistical Methods
1. Universe and Respondent Selection
The buildings selected for SOMA are those included in the Census Bureau's Survey of Construction (SOC). For SOC, the United States is first divided into primary sampling units (PSU's) which are sampled on the basis of population. Some geographic areas issue permits before a builder is allowed to build, and these areas are referred to as a "permit issuing" area. Other geographic areas do not require permits and are classified as a "NP - non-permit" issuing areas. The SOMA sample is drawn from permit issuing areas. Next, a sample of permit-issuing places is selected within each sample PSU. Finally, all buildings with five or more units within sampled places as well as a subsample of buildings with one to four units are selected for the SOC sample.
If there are more than 1,000 buildings completed in a month, a subsample of buildings is selected. The subsampling rate is dependent on the total number of buildings completed, but the total number of buildings in sample each month can never exceed 1,000.
The respondent universe consists of builders, building managers, rental agents, sales agents, and landlords of newly completed real estate developments or buildings containing five or more units. As one builder, manager, or agent may respond for more than one building, the size of this universe varies and is unknown.
The contact information comes from the SOC; the contact may be an owner, builder, rental agent, or sales agents, etc. The contact by the Census field representative may be either by telephone or personal visit. If the person has not been contacted previously, it sometimes is necessary to make the first contact in person. Subsequent interviews should be made by telephone if possible.
Field representatives will arrange interviews with someone who has direct knowledge of the renting or selling situation over an extended period of time. If the owner is contacted first, we will determine whether the owner or some other person is, or will be, managing the apartments. Then, the initial interview is conducted with the person who will be managing the apartment over the longest period of time. These responses are then keyed and data files are created at our National Processing Center.
2. Procedures for Collecting Information
Each quarter, a sample of buildings with five or more housing units in the SOC sample that were reported as completed during that quarter come into sample for SOMA. Buildings completed in non-permit issuing areas are excluded from consideration. Information on the proportion of units absorbed 3, 6, 9, and 12 months after completion is obtained for units in buildings selected in a given quarter in each of the next four quarters. Questionnaires for the selected properties are prepared and provided to regular Census Bureau interviewers for information collection.
For those buildings in the sample for the first time, an advance letter, describing the survey and asking for their participation, is mailed to the within a month of the interview. Contact is made with an owner, builder, rental agent, sales agent, or someone associated with the properties, for their initial “in person” interview. For subsequent interviews follow-up letters are mailed out and, if possible, telephone interviews are made about two weeks later.
Unbiased quarterly estimates are formed by multiplying the counts for each building by its base weight (the inverse of its probability of selection) and then summing over all buildings. The final estimate is then obtained by multiplying the unbiased estimate by a ratio estimate factor.
3. Methods to Maximize Response
The response rate is above 95 percent and is expected to remain at that level. Due to the high response rate, only normal data collection procedures are followed for nonresponse cases, i.e., supervisory personnel contact reluctant respondents.
4. Testing of Procedures
Discussions have been held about changing the method of data collection from paper questionnaires to computer-assisted survey information collection (CASIC). If such a change occurs, testing of the new data collection method will take place.
The SOMA has been conducted since 1971. SOMA is a longstanding survey and we are not encountering any problems with survey responses. No cognitive testing of survey questions has taken place since 1971 because no new questions have been added to the survey.
5. Contacts for Statistical Aspects and Data Collection
The individuals to contact are:
Medell E. Ford III
Chief, Housing and Health Surveys Branch
Field Division
Bureau of the Census
Phone: (301)763-2185
Robert R. Callis
Chief, Financial & Market Characteristics Branch
Social, Economic and Housing Statistics Division
Bureau of the Census
Phone: (301)763-3199
Aref N. Dejani
Chief, Longitudinal Surveys Branch
Demographic Statistical Methods Division
Bureau of the Census
Phone: (301)763-1797
| File Type | application/vnd.openxmlformats-officedocument.wordprocessingml.document |
| Author | H45596 |
| File Modified | 0000-00-00 |
| File Created | 2021-02-01 |