This list was calculated based on data from the Home Builders Association for Southeastern Michigan, which provided a list of all the communities in the nine-county region it tracks, the number of single-family housing permits in each community and the construction value listed on those permits, which were issued between January 2020 and February this year. An estimated sales price was calculated by adding 40 percent to the averageconstruction value of those permits to account for things like developer profit, land costs and other things.