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Frequently Asked Questions

Annual Population and Housing Estimates

Q.

What methodology does NCTCOG use to produce the Annual Population Estimates for cities and counties?

 

 

A.

For the Annual Estimates program, NCTCOG uses the housing unit method for estimating population. This is a straightforward calculation where estimated population is the product of the housing unit stock counts, residential occupancy rates, and household sizes. Persons in group quarters are added after the population in housing units is calculated. For a more detailed explanation of the methodology, see Population and Housing Estimates Program Notes.

 

 

Q.

Where does NCTCOG get the data used in producing the annual estimates?

 

 

A.

The housing unit information comes directly from cities each year, as do the data regarding population in group quarters. Single-family occupancy rates are calculated from Census ACS data. Multi-family housing occupancy rates are derived from data purchased from M/PF Research. Household sizes come from the U.S. Census Bureau's American Community Survey. NCTCOG gets water and sewer permit data, which are used to estimate housing units in unincorporated areas, from the Texas Commission on Environmental Quality.

 

 

Q.

What is the role of local cities in the annual estimates program?

 

 

A.

Each city with a population of at least 1,000 is asked to provide data about changes to the housing stock and persons in group quarters. These same cities are given the opportunity to review a preliminary estimate along with the underlying data prior to finalization and publication.

 

 

Q.

What does NCTCOG do for cities that have a population of less than 1,000?

 

 

A.

Population in these cities, along with population in unincorporated areas, is included in the “Remainder of County” figure in the NCTCOG publication.

 

 

Q.

Why are NCTCOG’s population estimates sometimes different from estimates produced by other organizations?

 

 

A.

Differences in estimates occur for a variety of reasons, most of which can be classified as either differences in methodology or differences in data inputs. When comparing NCTCOG estimates with estimates from other sources, methodology and data inputs for the various sources need to be compared as well. In addition, not all estimates are for the same time period. NCTCOG estimates population for January 1 of each year, while other organizations might produce figures for a different date.  For additional information about methodologies employed by various organizations, see Estimation Methodologies.

 

Land Use

Q.

What methodology does NCTCOG use to produce land use data?

 

 

A.

Since 2005, NCTCOG has used a methodology that includes analysis of parcel data, aerial photographs, development data from NCTCOG’s Development Monitoring program, field work, and city input. The most significant change from the prior methodology is the inclusion of parcel data. Prior to 2005, NCTCOG used aerial photographs and extensive local review in the production of its land use data. See NCTCOG 2005 Land Use Methodology for a more complete description of the methodology used since 2005.

 

 

Q.

How does NCTCOG land use from the various years compare?

 

 

A.

Over the years, NCTCOG has changed its methodology for assessing land use, making comparisons with land use for prior years problematic. The most significant changes affected the infrastructure, industrial, and commercial categories. The 2010 Land Use will follow the methodology used in 2005. Direct comparisons between land use data for different years are strongly cautioned.

 

 

Q.

Do NCTCOG’s land use codes correspond to use codes from other sources?

 

 

A.

NCTCOG devised its own land use classification based on the U.S. Geological Survey Land Use and Land Cover Classification System. In some cases, the classifications are similar, but NCTCOG has revised the USGC system to suit its own purposes. There is no specific effort on the part of NCTCOG to conform entirely to any other classification system. See NCTCOG Land Use Classification for a complete description of NCTCOG’s land use codes.

 

 

Q.

How often does NCTCOG update land use data?

 

 

A.

NCTCOG has been updating the land use data every five years and plans to continue this schedule as long as funding permits.

 

Development Monitoring

Q.

What is included in the Development Monitoring program?

 

 

A.

Any development that meets one of these criteria is included:  80,000 square feet, 80 employees on site, or 80 units (multi-family development only). In addition, all public schools, all mobile home parks, and all public universities or colleges are included.

 

 

Q.

Is a development the same as a building?

 

 

A.

A development is not necessarily a building. In most cases, each development will be just one building. However, some developments might be a collection of buildings. This can include a shopping development that is more than 80,000 square feet as a whole but does not have any one single building that would meet the criteria on its own. Another example is developments that are announced or merely conceptual. In these cases, the building locations or number of buildings are often not known when the development is added to the database.

 

 

Q.

Where does NCTCOG get the data included in the Development Monitoring program?

 

 

A.

NCTCOG staff use various news media, construction reports, and direct contact with local professionals and developers to identify and verify items included in the database.

 

 

Q.

What if I see something that needs to be updated or corrected in the development data?

 

 

A.

E-mail information to devmon@nctcog.org. NCTCOG staff will review all submissions prior to inclusion in the data set.

 

 

Q.

How often are the development data updated?

 

 

A.

The data are updated continuously. Therefore, the currency of the data for any particular development varies. As soon as NCTCOG staff become aware of a new development or status change, the data are updated.

 

Major Employers

Q.

Who is included in the Major Employers program?

 

 

A.

Any employer with at least 250 employees at a particular location is included in the program.

 

 

Q.

Where does NCTCOG get the data included in Major Employers program?

 

 

A.

NCTCOG staff use various news media and direct contact with employers to identify and verify items included in the program.

 

 

Q.

What about employers that have a lot of employees at different locations, but not a lot at one particular location?

 

 

A.

That employer will be included in the program if at least one of the locations has at least 250 employees. In addition, each location with at least 250 employees will also be included. If none of the locations has at least 250 employees on site, the employer is not included in the program. Employment of this type should be captured in small area estimates that NCTCOG produces periodically.

 

 

Q.

What if I see something that needs to be updated or corrected in the major employers data?

 

 

A.

E-mail information to devmon@nctcog.org. NCTCOG staff will review all submissions prior to inclusion in the data set.

 

 

Q.

How often are the major employers data updated?

 

 

A.

The data are updated as NCTCOG are alerted to a change. Therefore, the currency of the data for any particular employer varies. Currently there is no comprehensive, regular update of major employers data.

 

Demographic Forecast

Q.

What is the purpose of the Demographic Forecast?

 

 

A.

The NCTCOG Demographic Forecast is developed to provide a single source for infrastructure planning and resource allocations in the Metropolitan Planning Area. It was approved by the NCTCOG Executive Board on February 24, 2011.

 

 

Q.

Why are only some of the counties in the NCTCOG region included in the forecast?

 

 

A.

The twelve counties included in the forecast are those that are part of the metropolitan area as defined for regional transportation planning. Together, these twelve counties – Collin, Denton, Dallas, Ellis, Hood, Hunt, Johnson, Kaufman, Parker, Rockwall, Tarrant, Wise – make up the Metropolitan Planning Area (MPA). An expansion to all 16 counties in the NCTCOG region is proposed for future forecasting work.

 

 

Q.

Why are NCTCOG’s forecasts sometimes different from forecasts produced by other organizations?

 

 

A.

Differences in forecasts can result from differences in methodology or differences in data inputs. When comparing NCTCOG forecasts with forecasts from other sources, methodology and data inputs for the various sources need to be compared as well. In addition, close attention must be paid to definitions. For example, not all definitions of employment are the same. Exactly what is meant by each item being forecast must be well understood.

 

 

Q.

Where does NCTCOG get the data used in the Demographic Forecast?

 

 

A.

The data come from a variety of internal and external sources including the Census Bureau and other federal, state, and local sources. Some of the data, such as land use, are prepared by NCTCOG staff. Zone-to-zone travel times are provided by NCTCOG’s Transportation Department. Some of the inputs, such as the regional control totals, are prepared by independent consultants specifically for use by NCTCOG.

 

 

Q.

Why is household population different from total population?

 

 

A.

A household is any group of people, related or unrelated, that occupy a housing unit. A household can also consist of just one person. Thus, household population includes only persons living in housing units. This is in contrast to persons living in group quarters such as dormitories, correctional facilities, group home, and other similar facilities. Total population includes both household population and group quarters population.

 

 

Q.

What is the difference between NCTCOG’s Annual Population Estimates and Demographic Forecast?

 

 

A.

The annual population figure is an estimate, which is an approximation of the past based on observed data. The forecast figure is a projection, which is an anticipation based on various assumptions about future trends.

 

 

Q.

What are the plans for production of the next Demographic Forecast?

 

 

A.

NCTCOG is continually improving its forecasting program including both models and methodology. Future forecasting efforts will be designed to meet a broader range of planning needs while continuing to meet existing ones. Of particular interest is the ability to perform scenario modeling to assist the region in the assessment of potential policy questions. While forecasting work is ongoing, new forecasts are scheduled to be released no earlier than 2012 and no later than 2014.

 

Census Data

Q.

What is NCTCOG’s relationship to the U.S. Census Bureau?

 

 

A.

NCTCOG is a local affiliate of the U.S. Census Bureau through the State Data Center Program. In this role, NCTCOG is responsible for making Census data available to the public. NCTCOG also provides valued-added services such as mapping and general technical assistance in use of the data.

 

 

Q.

Where can I get Census data for areas outside the NCTCOG region?

 

 

A.

The Texas State Data Center has Census data for the entire state. Data for areas outside Texas are available directly from the Census Bureau or from other State Data Centers (each state and territory has its own data center).

 

 

Q.

What is the most current Census data available?

 

 

A.

The most current data available is from 2010 Census PL94-171 (redistricting file). Other current data includes releases of Census American Community Survey (ACS) data. A variety of current and historical Census data are available on the NCTCOG web site and through the Census Bureau’s American FactFinder.

 

 

Q.

What is the difference between race and ethnicity?

 

 

A.

For the Census Bureau’s purposes, the definitions of race and ethnicity do not necessary correspond to those used by others such as scientists or anthropologists. When looking at Census data concerning race or ethnicity, it is important to remember that the data are supplied by each individual and therefore subject to his or her own interpretation and identification. The Bureau recognized a distinct number of individual race categories and one multiple races category. In addition to race, individuals are asked to indicate ethnicity. The Bureau collects data on only one ethnic category, Hispanic or Latino. Merely for convenience, it might help to think of race as being genetic or biological and ethnicity as related to cultural affiliation or heritage. In this way, it might be easier to understand why every person will be in one of the race categories but not everyone will necessarily be in the one ethnic category.

 

 

Q.

What is the definition of “low income”?

 

 

A.

There is no official definition of “low income.” The term is defined in different ways depending on the application. See Low Income Definitions for examples of how some organizations have defined the term.

 

 

Q.

What is the definition of “minority” in terms of race and ethnicity?

 

 

A.

The broadly accepted description of this term includes any person that classifies themselves into at least one of the following race/ethnicity categories:  American Indian or Alaskan Native, Asian or Pacific Islander, Black, or Hispanic.

 

 

Q.

How are Census data used?

 

 

A.

Results of the decennial census are used to determine the number of seats each state has in the U.S. House of Representatives. In addition, the data are used in redrawing state legislative and congressional districts as well as determining distribution of funding for various government programs. Many state and local governments as well as private enterprises use Census data to make important decisions also.

 

 

Q.

What if I think the Census data for an area are wrong?

 

 

A.

The collection of detailed data for the entire U.S. and its territories is a huge undertaking. It is not surprising, then, that the mechanism for adjusting results of Census surveys is very limited. Local government officials can challenge Census figures through a specific process. Even if a challenge is made, there is no guarantee that it will be successful. NCTCOG cannot make any changes to Census figures without a directive from the U.S. Census Bureau. The Census Bureau has an established procedure for challenge of Census 2010 data; click here for more information.

 

 
 
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