Construction cost estimates are generated by HomeTech Publishing (www.hometechpublishing.com), which updates its database of construction costs quarterly, using construction commodity data, as well as labor cost information from a nationwide network of remodeling contractors. The company prepares a detailed construction estimate for each project, then adjusts this baseline cost for each city to account for regional pricing variations. Construction cost figures include labor, material, and subtrade expenses, plus industry-standard overhead and profit. However, project costs are based on estimates for hypothetical projects, with no reliable way to accommodate local and short-term fluctuations in supply and demand.
Resale value data for each project are aggregated from estimates provided by members of the National Association of REALTORS®. In cooperation with REALTOR® magazine, e-mail surveys containing project descriptions and three-dimensional illustrations, plus construction costs and median home price data for each city, are sent to some 150,000 appraisers, sales agents, and brokers. Respondents are instructed not to make judgments about the motivation of the homeowner in either the decision to undertake the remodeling project or to sell the house. The 2010-11 survey was in the field for approximately 8 weeks in June, July, and August of 2010. More than 3,000 survey respondents participated.