national multiple family submetering and allocation billing program ...

method such as RUBS or submetering) compared to instances when residents did not receive a
water bill, but the cost of water was included in the rent or homeowner’s dues (“in-rent”). Thus,
“in-rent” was chosen as the comparison group.
This type of variable transformation is necessary, because by definition there is not a
numerical order to the categories of billing type; that is, if the number “1” is assigned to an inrent
property, the number “2” to a RUBS property, and a “3” to a submetered property, it does
not make sense to describe submetered properties as being 2 units of billing method greater than
in-rent.
To create the dummy variables for type of billing method, each property was classified
using two variables, which were called RUBS and SUB. If residents at a property were billed
using a RUBS methodology, the property was assigned a “1” for the RUBS variable and a “0”
for the SUB variable. If residents at a property were billed using submeters, the property was
assigned a “0” for the RUBS variable and a “1” for the SUB variable. Finally, if residents at a
property did not receive a separate water bill from their rent or homeowner’s dues, the property
was assigned a “0” for the RUBS variable and a “0” for the SUB variable. Thus, to fully classify
billing method, both RUBS and SUB must be included in the model. The resulting B
coefficients demonstrate the differences in average water use between RUBS properties vs. inrent
properties and the differences in average water use between submetered properties vs. inrent
properties. If one of these variables was not included in the model, the comparison would
be between the variable included and all other property types; for example, if the SUB variable
only was included, the B coefficient would represent the average water savings in submetered
properties compared to in-rent and RUBS properties, adjusted for other factors included in the
model.
Many of the other variables found in one or more of the models presented below were
included as dichotomous variables. For most, if the amenity or characteristic was present or
“true” for a property, variable was coded as a “1” while the absence of the characteristic was
coded as a “0.” These variables included: senior citizen/retirement community, play area, and
cooling tower. The B coefficient for these factors represents the difference in average amount of
water observed in properties with the characteristics compared to those without, holding constant
the other factors included in the model. “Property was built before 1995” was coded so that
28 Prevalence of each characteristic can be found in Chapter 4 and Appendix B.
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