AHS: Do You Need Degree Days?

From: American Housing Survey (AHS) ListServ <ahs@huduser.gov>

The American Housing Survey microdata files include a variable, DEGREE, which indicates the heating or cooling degree days of the housing unit's local area. The codebook defines the variable this way:

DEGREE =
Average heating/cooling degree days
1 Coldest: 7,001+ heating degree days and < 2,000 cooling degree days
2 Cold: 5,500-7,000 heating degree days and < 2,000 cooling degree days
3 Cool: 4,000-5,499 heating degree days and < 2,000 cooling degree days
4 Mild: < 4,000 heating degree days and < 2,000 cooling degree days
5 Mixed: 2,000-3,999 heating degree days and 2,000+ cooling degree days
6 Hot: < 2,000 heating degree days and 2,000+ cooling degree days

HUD is considering dropping this variable when we redesign the survey and draw a new sample for the 2015 AHS. The reason is that having DEGREE on the file interferes with our ability to identify certain kinds of geography, such as states and Census divisions. Degree is set at the county level. There are certain Census divisions (and, even more so, states) where the combination of one of the degree codes and the division code identifies a section of the division whose population is less than 100,000. Under the Census Bureau's confidentiality rules, such small areas may not be identifiable on a public use file. Thus, we will not be able identify Census divisions on our public use file. As for states, there will certainly be states that are too small to identify no matter what. However, the presence of the DEGREE variable makes the job even more difficult.

Thus, HUD is proposing that we drop DEGREE from the survey beginning in 2015, so that we can identify Census divisions and at least some of the larger states. If any data users would be seriously inconvenienced by the loss of DEGREE, we would like to hear from you.

Dav Vandenbroucke
Senior Economist
U.S. Dept. HUD
david.a.vandenbroucke@hud.gov
202-402-5890

I disclaim any disclaimers.