You can find the data behind Sunday's construction costs story with the N.C. Department of Public Instruction (click on "construction costs" to the left). Note: I had to revise the 2005 averages in the spreadsheet because the Northern numbers listed are inaccurate.
When I started working on the series about school construction in Guilford County, one of the questions I had was "why did Northern High cost so much more than Reagan?" The reason? From board meetings, to blogs, to phone calls, I have heard people compare the two. I found in my research that there really is no "apples to apples" comparison, but you can come close by looking at inflation-adjusted cost per square foot and cost per student (a bit more difficult to come by).
When you look at the state comparison data, you can find reasons to criticize many school districts, not just Guilford. It just depends on the angle you take. When you take out projects in Wake, Mecklenburg and Guilford -- the state's largest school systems, cost averages come down. (but then you have to wonder, how valuable is data that omit school systems with the largest student populations and the most schools built?)
At any rate, advantages and disadvantages exist to comparing total building costs, per square foot costs and costs per student:
Total building costs: Tells you up front how much it cost to build a school, but doesn't include pieces that are harder to compare, such as furniture, equipment and soft costs. Some reasons to not compare total costs: One school system may benefit from buying all its furniture in bulk through one contractor as opposed to buying it per project. Another district may decrease its soft costs by working with one architect on several different schools or using a prototype design. The downside to total building costs is you can't really compare a 200,000 square foot school to a 80,000 square foot school.
Building cost per square foot: Allows comparisons in that you can better control for disparate building sizes and student populations (for example, a school may be built to house a disproportionate number of students with disabilities, which requires smaller class sizes). The downside to cost per square foot is that you can have schools with the same cost average, giving the appearance of equity, but one building can be more wasteful in space than the other.
Cost per student: Helps make up for the weakness in cost per square foot by taking into account wasteful space (i.e. two schools may have the same cost per square foot, but one devotes more square footage to students than needed). The downside to cost per student is that school districts use different formulas to allocate space and this may give a false representation (i.e. 30 students per classroom versus 25). Another issue is some students by law require more space than others (i.e. classroom wing for students with autism or the state's move to lower class sizes in K-3). The other downside is that student enrollments fluctuate, so a school may have been built to originally house 1,000 students but because of enrollment or programmatic changes, the population could shift to say, 900 students, or 1,100 students. That would change the cost per student, while the cost per square foot would stay the same.