national multiple family submetering and allocation billing program ...

local water use regulations or surcharges and regional predispositions or programs encouraging
conservation. Nevertheless, matching on other important characteristics was somewhat
challenging because, typically, impact properties are newer, and/or larger, and/or charge a higher
rent than in-rent properties.
A total of 77 properties were visited as part of the site visits for this study. Of the 77
visited properties, 64 met the necessary criteria for inclusion in the matched pair analysis. The
number of matched pairs available for analysis was 21 submetered/in-rent properties, and 14
RUBS/in-rent properties.
Comparison of Water Use in Matched Pair Sample to Postcard and Manager Survey Samples
To make the fairest comparison of water use between the matched properties, the average
water use per unit per year was calculated as the average of annual water use per unit across all
years within a match where water use data were present for both properties within the match. To
test the representativeness of the matched pair sample water use estimates compared to the
postcard survey sample and manager survey sample, comparisons were made between the
estimated water use in 2001 per unit in the postcard and manager survey sample to the estimated
annual water use per unit for the matched pairs. As can be seen in Table 5.20 below, there were
no statistically significant differences within the in-rent properties or the submetered properties
matched pair water use estimates compared to the postcard survey sample or the manager survey
sample. The in-rent matched pair water use estimate was higher the postcard and manager
survey estimates, while the submetered matched pair water use estimate was also slightly higher
than either other sample. Table 5.21 shows the same comparisons for the RUBS/in-rent pairs.
Here, the difference between the in-rent properties chosen for the matched pairs and the in-rent
manager survey respondents are significant (p