Appendix B: Data Sources

Overview of Data Sources

Population

Census data and county estimates from the U.S. Census Bureau were used to calculate the size of the population at the county-level for each of the Border States.  Population figures used for calculating the health provider-to-population ratios in this report are based on updated data from the U.S. Census Bureau, Population Division, Population Estimates Program (Release Date:  August 11, 2005).

Prevalence Data

Data for 2002 from the Behavioral Risk Factor Surveillance System (BRFSS) were used to estimate the proportion of the population:  without health coverage; ever diagnosed with diabetes; who are overweight or obese; who have had a dental visit within the past year; and, who currently have asthma.  In addition, the proportions of females who had a pap smear or mammogram were also estimated.

The BRFSS is a survey that collects information about adults (18 and older and living in households); persons younger than 18 are not represented by the survey results provided in this report.

While the sample allows estimates to be produced for areas, such as the Border regions in each of the Border States, most counties do not have large enough samples to produce reliable estimates for individual counties.

State Licensure Data

Agencies in each State that handle data for licensed health professionals were contacted to obtain data for the current report.  Among these were State boards for physicians, dentists, registered nurses, physician assistants, psychologists, and social workers.  Psychiatrists and three categories of specialty nurses were identified when specialty information or another designator was included in the data sets.

Delays in obtaining data resulted in inconsistencies in the reporting date of the data as most licensing boards process and compile data requests on an as needed basis and this Study may have had a lower priority rating at one board than at others.  Reporting dates were included in the respective tables in the report.

The health professions data used in this report, in most cases, were purchased from the respective Board in each State.  Licensure Boards most often receive requests for mailing lists.  Consequently, for some boards, a mailing list was purchased only when no other data were available for analysis.  Some boards were able to include additional variables to mailing lists.

State Health Data

Vital statistics, hospital discharge, and incidence data for selected diseases were also requested from State health departments to present the health status of the regions as well as State totals.  Healthy Border 2010 Objectives guided the selection of health indicators used in this report.

Description of Geocoding Process

State Licensure Data

Data received from State licensure boards or State organizations were “geocoded” using Geographic Information Systems (GIS) software in an effort to determine the location of the health professional.  This permitted assignment of health professionals to a county based on the county Federal Information Processing Standards (FIPS) code assigned by the GIS software.  The following process describes the method by which an address was “geocoded.”  The address used was determined by staff (in consultation with the suppliers of the data when possible) to best represent the practice location of the health professional.  Using batch processing, on the first pass, addresses were matched only on the exact street name, house number and zip code.  On the second pass ^[148] , addresses were matched by “ relaxing ” the zip code; this allowed a match for address in a different zip code.  On the third pass, street name and house number for the address were relaxed to allow matches for parameters similar to address components (such as misspellings to be matched to the address).  On the final geocoding pass (usually by this stage only a small percentage of records were not matched), records were matched by zip code only.  Once these passes were complete, remaining unmatched records were viewed through interactive mode in GIS to determine if a match could be made by searching for visible errors in the address field.  Once geocoding was completed, data were moved into Statistical Package for the Social Sciences (SPSS) software.  The remaining unmatched records were assigned a county in SPSS based on the city name.  For example, since PO Box addresses could not be geocoded, they were assigned a county FIPS code based on the name of the city.

State Health Data

Health related information such as vital statistics, hospital discharge, and incidence data, were usually assigned a county code by the State agency/office responsible for the data.  Data reported here reflect place of residence of each case, not the place of occurrence.

Data from Licensing Boards in Texas

Data for each of the health professions discussed in the current report were received from each of the respective licensing boards in Texas.  While special issues with each of the data sets will be discussed below, the following table highlights the proportion of data that was not available (NA) by type of variable for the three types of primary care professionals: 

Proportion of Missing Data for Physicians, Dentists, and Registered Nurses in Texas

* Reflects direct patient care physicians only. 

** Reflects private practice dentists only. 

NA= Not available

A= Available

Physicians and Physician Assistants

License data for Texas physicians and physician assistants (PAs) were received from the Texas State Board of Medical Examiners and reflect a date of September 2003.  Physician data used in this analysis contained some of the richest/most complete data available in each of the Border States.  In addition to demographics, the presence of indicators to allow for identification of direct patient care, as well as specialty or primary care, and a category of hours worked per week by those physicians were all available.  Data for physician assistants contained similar information as that of physicians with the exception of specialty field and number of hours worked.

An added benefit of data for both physicians and PAs, was the availability of a practice address.  The practice address information was geocoded in order to assign the health practitioner at the county-level.

Dentists

License data for Texas dentists were received from the Texas State Board of Dental Examiners and reflected a date of September 2003.  License data for dentists used in the analysis contained demographics for gender and age, but information regarding race/ethnicity was not available.  The strength of this data set was the availability of a field which allowed for the identification of dentists in private practice as well as by general or specialty areas of dentistry.  However, a drawback of the dentists' data was that information regarding the number of hours per week is not collected by the Board.

License data for Texas dentists contained a primary and secondary mailing address.  However, it was not known which, if either, of the addresses, identified a practice address.  Thus, the primary address was geocoded first followed by the secondary mailing address if the first address could not be geocoded.

Registered Nurses

License data for Texas registered nurses were received from the Texas Board of Nurse Examiners and reflected a date of September 2003.  License data for nurses used in this analysis contained some of the most complete data available for each of the Border States.  In addition to demographics, there are indicators present to allow for identification of nurses employed on a full- or part-time basis, as well as by specialty.  However, a drawback of the field for part-time employment in nursing is that “part-time” is based on the nurses' interpretation since there are no guidelines in place to identify the number of hours associated with part-time employment.  Thus, each nurse may interpret part-time differently (for example, less than 40 hours, less than 30 hours, or less than 20 hours per week).

An additional drawback of the nurses' data is that only a practice zip code was available.  One of the problems associated with having only the practice zip code, rather than the entire practice address, is that the record is assigned to the center of the zip code reported as the practice zip code which may or may not fall into the actual county where the nurse is working when the practice zip code is geocoded (zip codes may overlap county boundaries).

When available, the practice zip code was geocoded on a first run through GIS.  If a practice zip code was not available, the address provided by the Board was geocoded in order to assign the nurse record to a particular county.

Psychologists

Data for Texas psychologists were received from the Texas State Board of Examiners of Psychologists and reflected a date of October 2003.  Data for psychologists did not contain information regarding demographics nor employment by full- or part-time status.  Furthermore, it was unknown if the psychologist provides patient care in a clinical setting.  An additional problem was the availability of only one address which was geocoded to determine the location of the psychologist's practice address.  The problem with this assumption was the inability to determine whether the address in the data set reflected a business/practice address.

Social Workers

Data for social workers in Texas were received from the Texas State Board of Social Worker Examiners and reflects data for September 2003.  However, the data received did not contain information regarding demographics nor employment by full- or part-time status.  Furthermore, while a field allowed for the identification of Master's level social workers, it was unknown if the social worker was providing patient care in a clinical setting.  An additional caveat was not knowing whether the city and State address provided reflected a mailing or practice location.

Since only the city and State names were available, a county identifier was assigned by using data from the nurses file which contains county FIPS codes.  If a county FIPS code was not assigned by this method, a county identifier was manually assigned by matching the city name to a county.

Data from Health Offices in Texas

Vital Statistics

Vital statistics data for 2002 were received from the Bureau of Vital Statistics, Texas Department of Health.

Hospital Discharges

Hospital discharge data for 2002 were received from the Texas Health Care Information Council, Center for Health Statistics, Texas Department of Health.

Incidence Data

Breast and Cervical Cancer

Data for breast and cervical cancer cases diagnosed in 2001 were received from the Texas Cancer Registry, Texas Department of Health.

HIV/AIDS

Number of HIV/AIDS cases diagnosed in 2002 were retrieved from http://www.tdh.state.tx.us/hivstd/stats/pdf/qr20024.pdf, on May 19, 2004.

Hepatitis A and B

Data for Hepatitis A and B for cases diagnosed in 2002 were received from the Immunization Division, Texas Department of Health.

Tuberculosis

Number of tuberculosis (TB) cases diagnosed in 2002 were retrieved from http://www.tdh.state.tx/tb/CasesByCounty.htm, on May 17, 2004.

Immunizations

Information about childhood immunization status for 2003 was obtained from the Centers for Disease Control and Prevention, National Immunization Program (NIP).  While State level data were available through the National Immunization Survey (NIS), results were not available for all race/ethnic groups.  For Texas, State level results were only available for Non-Hispanic Whites and Hispanics.