Technical Appendix for 1993 QUALITY OF DATA Completeness of registration All States have adopted laws requiring the registration of births and deaths and the reporting of fetal deaths. It is believed that more than 99 percent of the births and deaths occurring in this country are registered. Reporting requirements for fetal deaths vary from State to State (see "Comparability and completeness of data"). Overall reporting is not as complete for fetal deaths as for births and deaths, but it is believed to be relatively complete for fetal deaths at a gestation of 28 weeks or more. National statistical data on fetal deaths include only fetal deaths occurring at a stated or presumed gestation of 20 weeks or more. Massachusetts data--The 1964 statistics for deaths exclude approximately 6,000 deaths registered in Massachusetts, primarily to residents of that State. Microfilm copies of these records were not received by NCHS. Figures for the United States and the New England Division are affected also. Amended records for Alaska and New Jersey--Numbers of deaths occurring in Alaska and New Jersey for 1993 are in error for all causes of death combined and for selected causes because NCHS did not receive all of the States' records and did not receive changes resulting from amended records. An estimate of the effect of these omissions can be derived by comparing NCHS counts of records processed through the VSCP with counts prepared by the respective States as shown in table E. Differences are concentrated among selected causes of death, principally Symptoms, signs, and ill-defined conditions (ICD-9 Nos. 780-799) and external causes. Quality control procedures Demographic items on the death certificate--As previously indicated, for 1993 the mortality data for these items were obtained from two sources-- photocopies of the original certificates furnished by the Virgin Islands and Guam and electronic data records furnished by the 50 States, the District of Columbia, New York City, and Puerto Rico. For the Virgin Islands and Guam, which sent only copies of the original certificates, the demographic items were coded for 100 percent of the death certificates. The demographic coding for 100 percent of the certificates was independently verified. For areas sending electronic data records, a sample of 70-80 records per month for each registration area is used to monitor quality of coding. Under this procedure, each sample record is independently coded by NCHS staff and compared to the State code assignments. NCHS/State differences are adjudicated to ascertain the source of the error and need for corrective action. The estimated average outgoing error rate for all demographic items in 1993 was 0.25 percent. The error rate is a combined measure of State coding, key entry and processing errors made in the process of preparing the statistical file. It is noted, however, that these types of errors are not necessarily randomly distributed in the file and may therefore escape detection through sample verification. Other NCHS procedures such as detailed computer edits, tabular evaluation and procedure review are used to reduce some systematic errors. - 1 - Table E. Numbers of deaths and ratios of deaths for selected causes as tabulated by State of occurrence and NCHS, 1993 [Data by place of occurrence include deaths of nonresidents. Numbers after causes of death are category numbers of the Ninth Revision, International Classification of Diseases, 1975] _____________________________________________________________________________ Ratio Causes Alaska NCHS AK/NCHS _____________________________________________________________________________ All causes........................... 2,319 2,382 1.01 Symptoms, signs, and ill-defined conditions...............780-799 37 62 0.60 Accidents and adverse effects ..........................E800-E949 301 372 0.81 Motor vehicle accidents ..........................E810-E825 124 120 1.03 All other accidents and adverse effects.........E800-E807,E826-E949 177 252 0.70 Suicide....................E950-E959 140 98 1.43 Homicide and legal intervention ..........................E960-E978 58 42 1.38 All other external causes..E980-E999 11 2 5.50 _____________________________________________________________________________ Ratio Causes New Jersey NCHS NJ/NCHS _____________________________________________________________________________ All causes........................... 71,198 71,090 1.00 Symptoms, signs, and ill-defined conditions...............780-799 320 862 0.37 Accidents and adverse effects ..........................E800-E949 2,084 2,058 1.01 Motor vehicle accidents ..........................E810-E825 814 791 1.03 All other accidents and adverse effects.........E800-E807,E826-E949 1,270 1,267 1.00 Suicide....................E950-E959 607 551 1.10 Homicide and legal intervention ..........................E960-E978 441 417 1.06 All other external causes..E980-E999 185 82 2.26 _____________________________________________________________________________ Medical items on the death certificate--The same procedures used for demographic data are used for the medical items. For the 38 States sending electronic files, the average outgoing error rate in 1993 was estimated at 2.5 percent for underlying cause data, and 5.0 percent for multiple cause-of-death data. - 2 - For the remaining 12 States, the District of Columbia, New York City, Puerto Rico, the Virgin Islands, and Guam, NCHS coded the medical items for 100 percent of the death records. A 1-percent sample of the records was coded independently for quality control purposes. The estimated average error rate for these areas was 4.0 percent. Demographic items on the report of fetal death--As previously indicated, for 1993 the fetal-death demographic data were obtained from two sources: coded records in electronic form from 43 registration areas and photocopies of the original certificates furnished by the remaining registration areas. For the 12 registration areas submitting photocopies, a small number of the records were coded under contract by the U.S. Bureau of the Census early in the data year before NCHS assumed responsibility for coding photocopies of records. State-coded records may incorporate corrections made to the records as a result of queries whereas data codes from photocopies would be less likely to incorporate all corrections. Beginning with data year 1993, quality control for fetal-death data was limited to computer edit checks, code validations, and comparisons of tabulated data with that for the previous year. Dual-coding of a sample of fetal-death records was not performed due to resource constraints. In 1993, problems that occurred during the conversion of selected State- coded data to NCHS format were detected for Colorado, New York State, and Washington. The effected items were father's Hispanic origin for Colorado; other terminations, medical risk factors, obstetric procedures and complications of labor and/or delivery for New York State; and congenital anomalies for Washington. While corrections were not made to the 1993 data, changes were instituted to avoid these processing errors in future data. Other control procedures--After coding and data entry are completed, record counts are balanced against control totals for each shipment of records from a registration area. Editing procedures ensure that records with inconsistent or impossible codes are modified. Inconsistent codes are those, for example, indicating a contradiction between cause of death and age or sex of the decedent. Records so identified during the computer editing process are either corrected by reference to the source record or adjusted by arbitrary code assignment (43). Further, conditions specified on a list of infrequent or rare causes of death are confirmed by the certifier or a State Health Officer. All subsequent operations in tabulating and in preparing tables are verified during the computer processing or by statistical clerks. Estimates of errors arising from 50-percent sample for 1972 Death statistics for 1972 in this report (excluding fetal-death statistics) are based on a 50-percent sample of all deaths occurring in the 50 States and the District of Columbia. A description of the sample design and a table of the percent errors of the estimated numbers of deaths by size of estimate and total deaths in the area are shown in the Technical Appendix from Vital Statistics of the United States, 1972. - 3 -