USER NOTES User notes supply file purchasers with additional or corrected information which becomes available after the technical documentation or files are prepared. They are issued in a numbered series and automatically mailed to all users who purchase technical documentation from the Census Bureau. Other users may obtain them by subscribing to the user note series. Contact Customer Services (301-763-4100) for subscription information. Each user note has a cover sheet which should be filed following this page. Technical documentation replacement pages will follow the cover sheet. These pages need to be filed in their proper location and the original pages destroyed. Replacement pages can be readily identified, since they have the user note date on the lower outside portion of each page. USER NOTE ORDERING INFORMATION Additional information concerning this file may be available at a later date. User notes, along with technical notes, are sent automatically to all Census Bureau data purchasers. If the user/technical notes should be sent to another address, please complete the coupon below and return it to Customer Services at the address shown. Users who purchase from other sources may subscribe to the user/technical note series at a cost of $40 annually. Use the Customer Services order form at the end of chapter 1. Be sure to indicate the series subscription (Redistricting file, STF 1, etc) on the order form. Data User Services Division Customer Services Branch Bureau of the Census Washington, DC 20233 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Name of File: Census of Population and Housing, 1990: Summary Tape File 3 on CD-ROM (Puerto Rico) Please send me any information that becomes available later concerning the file listed above. Name: Address: City and State: ZIP Code: CENSUS OF POPULATION AND HOUSING, 1990: SUMMARY TAPE FILE 3 ON CD-ROM (PUERTO RICO) USER NOTE 1 Age Reporting--Review of detailed 1990 information indicated that respondents tended to provide their age as of the date of completion of the questionnaire, not their age as of April 1, 1990. In addition, there may have been a tendency for respondents to round up their age if they were close to having a birthday. It is likely that approximately 10 percent of persons in most age groups are actually 1 year younger. For most single years of age, the misstatements are largely offsetting. The problem is most pronounced at age 0 because persons lost to age 1 may not have been fully offset by the inclusion of babies born after April 1, 1990 and because there may have been more rounding up to age 1 to avoid reporting age as 0 years. (Age in completed months was not collected for infants under age 1.) The reporting of age 1 year older than age on April 1, 1990 is likely to have been greater in areas where the census data were collected later in 1990. The magnitude of this problem was much less in the three previous censuses where age was typically derived from respondent data on year of birth and quarter of birth. (For more information on the design of the age question, see the discussion on comparability under "Age" in appendix B.) Mobile Homes--During data review we observed that certain units were incorrectly classified as mobile homes rather than single family or multi-family units. Accordingly, caution should be exercised in using the data for mobile homes. Vacancy Status--Caution should be exercised when using data reported on "Vacancy Status." The category "Rented or sold, not occupied" may include a significant number of housing units which should have been classified as "Seasonal, recreational, or occasional use." October 1993 CENSUS OF POPULATION AND HOUSING, 1990: SUMMARY TAPE FILE 3 ON CD-ROM (PUERTO RICO) USER NOTE 2 Clarification of Differences Between 100-Percent Counts and Sample Estimates--Estimated population and housing unit totals based on tabulations from only the sample questionnaires (sample tabulations) may differ from the official counts as tabulated from every census questionnaire (100-percent tabulations). Such differences result, in part, because the sample tabulations are based on information from a sample of households rather than from all households (sampling error). Differences also can occur because the interview situation (length of questionnaire, effect of the interviewer, and so forth) and the processing rules differ somewhat between the 100-percent and sample tabulations. These types of differences are reflected in what is called nonsampling error. (For a more detailed description of nonsampling error, see Appendix C, "Accuracy of the Data," in the technical documentation.) The 100-percent data are the official counts and should be used as the source of information on items collected on the 100-percent questionnaire, such as age, number of rooms, and tenure in housing. This is especially appropriate when the primary focus is on counts of the population or housing units for small areas such as census tracts/BNA's and block groups. For estimates of counts of persons and housing units by characteristics asked only on a sample basis (such as education, labor force status, income, and source of water), the sample estimates should be used within the context of the error associated with them. Many users are interested in tabulations of items collected on the sample cross-classified by items collected on a 100- percent basis such as age, sex, and housing units by tenure. Given the way the weights were applied during sample tabula- tions, generally there is exact agreement between sample estimates and 100-percent counts for total population and total housing units for most geographic areas. At the state, sample estimates and 100-percent counts for population by age, sex, and for housing units by tenure, number of rooms, and so on would be reasonably similar and, in some cases, the same. At smaller geographic levels, including census tract/BNA, there is still general agreement between 100-percent counts and sample estimates of total population or housing units. At smaller geographic levels, however, there will be expected differences between sample estimates and 100- percent counts for population by age, sex, and for housing units by tenure, number of rooms, and so on. In these cases, users may want to consider using derived measures (such as means, and medians) or percent distributions. Whether using absolute numbers or derived measures for small population groups and for a small number of housing units in small geographic areas, users should be cautioned that the sampling error associated with these data may be large. As we have done in previous censuses, the Census Bureau will evaluate the quality of the data and make this information available to data users. In the meanwhile, both 100-percent and sample data serve very important purposes and, therefore, should be used within the limitations of the sampling and nonsampling errors. October 1993 CENSUS OF POPULATION AND HOUSING, 1990: SUMMARY TAPE FILE 3 ON CD-ROM (PUERTO RICO) USER NOTE 3 Appendix G. The latitude and longitude values shown by tick marks in the margins of the Municipio Subdivision Outline Maps in appendix G are approximate. They area shown only for general reference. They are displayed accurately on the Area and Municipio Outline Maps. October 1993 CENSUS OF POPULATION AND HOUSING, 1990: SUMMARY TAPE FILE 3 ON CD-ROM (PUERTO RICO) USER NOTE 4 Data presented in matrices H44A "Median Gross Rent as a Percentage of Household Income in 1989" and H49A "Median Selected Monthly Owner Costs as a Percentage of Household Income in 1989 and Mortgage Status" in Summary Tape File 3 (Puerto Rico) are not consistent with Appendix B - Definitions of Subject Characteristics. When the median falls in the lower interval of the tabula- tion distribution, the estimated value obtained by linear interpolation is shown rather than the upper value of the category followed by a minus sign (-). The lower interval has an assumed range of 0 to 19.9 percent. October 1993 CENSUS OF POPULATION AND HOUSING, 1990: SUMMARY TAPE FILE 3 ON CD-ROM (PUERTO RICO) USER NOTE 5 The data shown in this product for persons enumerated in "visible in street locations" are incorrect and should not be used. Only the 100-percent data shown in data products, such as Summary Tape Files (STF's) 1 and 2 and in the 1990 CP-1, General Population Characteristics [State] reports should be used for persons enumerated at "visible in street locations." During "Shelter and Street Night Enumeration," all visible persons on the streets were asked only the basic 100-percent population questions (age, sex, marital status). During census processing of sample data, information from the long-form questionnaire was inadvertently assigned to a very small percentage of the visible in street population. October 1993 CENSUS OF POPULATION AND HOUSING, 1990: SUMMARY TAPE FILE 3 ON CD-ROM (PUERTO RICO) USER NOTE 6 The estimated population totals for persons in group quarters, specifically by group quarters type, that are based on census sample tabulations may differ from comparable figures shown in 100-percent tabulations. Such differences result, in part, from sampling variability which occurs because information was obtained from a sample of the population rather than from all persons. Differences also occur because of nonsampling errors which affect the 100- percent and sample data. Examples of nonsampling errors include respondent and enumerator errors, processing errors, and nonresponse. The 100-percent data are the official counts and should be used as the source for data on group quarters type when the primary focus is on counts of the population in group quarters, especially for small areas such as census tracts/BNA's or blocks. When the group quarters population is shown by characteristics covered only on a sample basis (for example, education, labor force status, income, etc.), the sample figures should be used within the context of the sampling variability associated with them. For more information on the limitations of 100-percent and sample data for persons in group quarters and the classification of group quarters type, see appendix B. October 1993 CENSUS OF POPULATION AND HOUSING, 1990: SUMMARY TAPE FILE 3 ON CD-ROM (PUERTO RICO) USER NOTE 7 Employment Status--The procedures used to classify persons by employment status in the 1990 Census of Puerto Rico differed from those used for the United States in the handling of responses concerning layoff status. A significant number of persons in Puerto Rico who are classified as "not in labor force" would have been incorrectly classified as "unemployed" if the classification procedures for Puerto Rico had been identical to those for the United States. October 1993 CENSUS OF POPULATION AND HOUSING, 1990: SUMMARY TAPE FILE 3 ON CD-ROM (PUERTO RICO) USER NOTE 8 Table (Matrix) P99, Imputation of Population Items--The data in table (matrix) P99 are shown incorrectly because of an error in processing that tallied 100-percent data items rather than sample data items. The corrected figures for Puerto Rico (Summary Level 040) are: No items allocated 1758590 One or more items allocated 1763447 October 1993 CENSUS OF POPULATION AND HOUSING, 1990: SUMMARY TAPE FILE 3 ON CD-ROM (PUERTO RICO) USER NOTE 9 Poverty Status in 1989--A minor error has been detected in the determination of poverty status for persons and families in the 1990 census. For families with a householder or spouse under the age of 18, an incorrect poverty threshold was used to determine poverty status. This resulted in the misclassification of 720 families in the United States and 6 families in both Puerto Rico and the U.S. Virgin Islands as either poor or not poor. Due to the small number of families affected, no correction has been applied. Weighted estimates of affected cases are listed below by State. Families misclassified as: Poor Not Net difference in Poor number poor United States, excluding Puerto Rico and the Virgin Islands 388 332 -56 Alabama 11 2 -9 Alaska 7 0 -7 Arizona 15 0 -15 Arkansas 0 0 0 California 62 75 13 Colorado 9 0 -9 Connecticut 0 7 7 Delaware 0 0 0 District of Colombia 0 0 0 Florida 22 21 -1 Georgia 25 0 -25 Hawaii 0 0 0 Idaho 12 0 -12 Illinois 3 0 -3 Indiana 4 0 -4 Iowa 6 0 -6 Kansas 0 9 9 Kentucky 25 22 -3 Louisiana 17 11 -6 Maine 0 0 0 Maryland 0 3 3 Massachusetts 0 25 25 Michigan 7 2 -5 Minnesota 0 0 0 Mississippi 4 0 -4 Missouri 5 0 -5 Montana 3 0 -3 Nebraska 0 0 0 Nevada 0 0 0 New Hampshire 0 0 0 New Jersey 0 15 15 New Mexico 0 0 0 New York 4 49 45 North Carolina 0 22 22 North Dakota 0 0 0 Ohio 0 13 13 Oklahoma 6 15 9 Oregon 0 0 0 Pennsylvania 30 0 -30 Rhode Island 0 0 0 South Carolina 10 0 -10 South Dakota 0 0 0 Tennessee 2 3 1 Texas 65 18 -47 Utah 0 18 18 Vermont 0 0 0 Virginia 8 2 -6 Washington 7 0 -7 West Virginia 5 0 -5 Wisconsin 6 0 -6 Wyoming 8 0 -8 Puerto Rico 0 5 5 Virgin Islands 0 1 1 October 1993