The Sun's housing analysis uses the Maryland Department of Planning's most recent growth forecasts to calculate how many new dwellings would be needed to keep pace with job growth in the region - Baltimore and its five suburban counties. As the series describes, jobs are expected to be created in numbers far greater than there is housing to accommodate workers. Not enough new homes are being built, and more homes will be taken up by retirees as the vast baby boom generation leaves the work force.
To reach that conclusion,The Sun had to determine the ratio of jobs to homes. The average home will have enough workers to fill a certain number of local jobs, and the newspaper needed to calculate that ratio over time to see whether jobs and housing would match up. If the number of workers in the average home drops, then more housing will be needed just to stay even, much less to keep up with job growth.
The Sun calculated these ratios by melding state forecasts, a step the state does not take. The newspaper found that a Baltimore-area home supplies workers for 1.6 local jobs and that this ratio will hold for the next few years. But it will slip continually as the baby boom generation retires. Meanwhile, the region will be adding jobs.
The calculation includes the effect of commuting because thousands of residents work outside the region, primarily around Washington. If anything, the impact is understated because the analysis assumes that the share of commuters - last measured in 2000 - will remain steady. But Washington workers have been moving to the Baltimore region in increasing numbers in search of cheaper housing, a trend that's expected to continue.
The state's forecasts were prepared last fall for every five-year period through 2030. Three were key to the analysis:
Households: Rather than projecting housing units, the state Planning Department forecasts households - a commonly used stand-in for the number of occupied dwellings. The department based its forecast on information from the six jurisdictions about the amount of homebuilding allowed by current regulations, including some planned changes to the rules that have not yet taken effect. For instance, Howard County's "general plan" calls for more intense development of downtown Columbia. Without major zoning changes, much of the land permitted for residential development in Baltimore's suburbs will be used up by 2030.
Jobs: The state's employment forecast includes self-employment, even part time, and therefore reflects the fact that some people work more than one job. The Sun took this multiple job holding into account in the analysis, adjusting the ratio so the housing shortage is not overstated.
John Hopkins, who studies the area economy for Towson University's RESI research and consulting arm, said the projections are, if anything, conservative. That's because they do not include most of the 40,000 jobs that local officials expect the national military base realignment - often referred to as BRAC - will bring to the region. Wanting to be cautious, state planners included only 13,800 BRAC jobs. Planners also factored in business cycles but did not try to predict when recessions will occur.
Available workers: The state's labor force forecast tries to capture the effect of aging baby boomers. State planners believe that boomers will work longer than their elders did but will retire eventually and that most will probably stay in the area when they do.