Letter from Loudoun County Preservation and Conservation Coalition

May 1, 2017

To: Loudoun County Board of Supervisors

FROM: Members of the New Comprehensive Plan Review Committee of the Loudoun County Preservation and Conservation Coalition


The Housing Needs Assessment prepared by George Mason University Center for Regional Analysis et al (February 2017) in not a  valid foundation for setting housing policies for the New Comprehensive Plan for the following reasons:

The Study uses a “Static Model” based on a projection of 107,100 new jobs created in Loudoun between 2015-2040.  It converts this to “housing needs” through a series of fixed ratios based on 2014/15 housing data, however:

  1. The study fails to account for likely and important changes in its driving assumptions over the next 20 years
  • Assumes no changes in the types of local housing desired;
  • Continues current patterns of commuting to work versus local employment;
  • Assumes no change in Loudoun’s local employment growth vs  regional growth;
  • Fails to distinguish between employment generated by growth in the local population from employment created independent of population; 
  1. The study fails to account for the impact and opportunity presented by Metro
  • Assumes no Metro impact on commuting and traffic patterns
  • Assumes no impact from Metro based urban and higher density housing availability
  1. The study does not consider significant changes already underway in regional housing and commuting patterns.
  • In 2000, 50% of local residents worked within Loudoun
  • In 2014, 56% lived and worked within Loudoun
  • The study assumed no further improvement in this figure 
  1. The study fails to take account of uncertainty in its driving assumptions and projections and simply provides single number projections,
  • Does not consider the uncertainty in long range  economic growth and job creation projections
  • Does not explore the impact of  this  uncertainty on its housing demand projections
  • Does not explore the risk inherent in making decisions based on its uncertain projections
  1. The Study does not consider the negative impacts on its forecast to local values cited as important to Loudoun attractiveness in recent Envision sessions and in recent surveys
  • Increased sprawl;
  • Increased traffic congestion;
  • Overcrowding schools and public facilities;
  • Damage to historic areas and sites.
  • Reduced opportunities for parks and open space.
  • Limited development of the Silver Line Tax District;
  • Reduced incentives for renewing older areas in Eastern Loudoun;
  • Damage to natural areas, water quality and habitat
  • Reduction in land available for agriculture and other business
  • Undermining of Loudoun’s fiscal policies and tax structure.



The GMU Housing Needs Assessment is an example of “Static” modeling.  It contains a lot of  background material on the status of housing in Loudoun County at the baseline of 2015.  It is professional in the manner in which it  lists its assumptions and methodology.

Nonetheless, the GMU Study projections are not valid as the basis for reconsidering the County’s existing housing projections with all the inherent risks to the quality of life of Loudoun’s present families and economy.

The study can, however, serve as a useful warning of the consequences of unconstrained approval and construction of single family homes to the maximum extent allowed by current zoning and land use regulations.


To improve the usefulness of this and similar studies we suggest that the County invest in a dynamic and flexible planning and modeling system that would allow the County to more easily analyse the The , i.e. What If Analyses.

Beyond its use for long range planning, such a modeling capability would support

  1. Development of plans for major new opportunities like Metro which consider complex relationships within multiple factors
  2. Examination of the impacts of major development proposals on multiple factors of interest to decision-makers and residents

We however realize that, due to resource and time constraints, it may not be possible in the short term to establish the flexible modeling system described above. We however recommend that the following analyses be performed and, as best possible with the existing tools, models and resources, assess and document the resulting impacts.

By consolidating the results of these analyses we are convinced that the County will have a much better foundation for setting housing policies for the New Comprehensive Plan. In addition, it will also have acquired a deeper understanding of the various interdependencies and impacts of various scenarios The recommended analyses include:

  1. Develop alternative high and low scenarios of driving assumptions based on the analysis of the potential uncertainty in the forecasts
  2. Examine trends and uncertainties in relationships between driving assumptions and employment/housing figures and calculate high and low estimates for those relationships as they evolve over the next 20 years
  3. Dissagregate employment categories to better identify and differentiate primary and secondary demand, the relationship between employment in Loudoun and elsewhere and to better understand alternative housing choices
  4. Define the major impacts of housing growth projections on key factors identified as important to Loudoun attractiveness like drive times, congestion, school crowding, landscape degradation degradation, the rural economy and County financial condition
  5. Combine these driving, relationship and impact factors to develop alternative scenarios for housing growth which display the impacts of higher and lower driving assumptions, changes in relationships between factors and the  effects of lower vs higher Loudoun attractiveness .
  6. Develop alternative policy scenarios which propose different combinations of critical factors like land use and location policies, transportation policies, Metro approaches and so on
  7. Consider the alternative policy cases under alternative growth scenarios to understand impacts on critical factors important to residents, the impact on County financial conditions and to quantify the risks of alternative policies given the uncertainty of the forecasts


Respectfully Submitted by Members of the New Comprehensive Plan Review Committee of the Loudoun County Preservation and Conservation Coalition

Al Van Huyck
Mitch Diamond
Nicole Hamilton
Gem Bingol
Jeff Freeman
Martha Polkey
Ard Geller
Bob Shuey

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