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. 2021 Jun 18;109:102491. doi: 10.1016/j.jeem.2021.102491

Table 4.

Difference-in-difference estimates expressed in terms of the aggregate change in water consumption by billing cycle.


(A) Bill 1
(1) (2) (3)
DID
DID (Min)
DID (Max)
Estimated %Change in average daily consumption
 Residential 12.19% 11.40% 12.75%
 Commercial −34.69% −35.66% −34.10%
 Schools −61.02% −66.18% −55.78%
Estimated change in water consumption over 30 days (in gallons)
 Residential 176,872,066 165,514,822 185,033,195
 Commercial −116,286,309 −119,545,977 −114,306,909
 Schools −12,754,793 −13,833,610 −11,660,464
 Net Effect
47,830,964
32,135,235
59,065,822
(B) Bill 2
DID
DID (Min)
DID (Max)
Estimated %Change in average daily consumption
 Residential 26.11% 25.86% 26.62%
 Commercial −18.13% −19.99% −14.87%
 Schools −62.73% −66.31% −60.31%
Estimated change in water consumption over 30 days (in gallons)
 Residential 378,956,947 375,300,138 386,292,542
 Commercial −60,767,151 −67,007,787 −49,851,573
 Schools −13,113,390 −13,861,836 −12,606,774
 Net Effect
305,076,406
294,430,515
323,834,195
(C) Bill 3
DID
DID (Min)
DID (Max)
Estimated %Change in average daily consumption
 Residential 24.61% 23.49% 25.86%
 Commercial −12.19% −13.84% −9.70%
 Schools −59.30% −67.18% −53.37%
Estimated change in water consumption over 30 days (in gallons)
 Residential 357,125,396 340,922,799 375,300,138
 Commercial −40,866,244 −46,406,385 −32,507,543
 Schools −12,396,722 −14,042,579 −11,157,327
 Net Effect
303,862,429
280,473,835
331,635,267
(C) Bill 4
DID
DID (Min)
DID (Max)
Estimated %Change in average daily consumption
 Residential 35.93% 35.66% 36.21%
 Commercial −11.04% −14.02% −9.24%
 Schools −29.74% −44.35% −15.89%
Estimated change in water consumption over 30 days (in gallons)
 Residential 521,503,131 517,561,515 525,452,639
 Commercial −37,014,630 −46,983,604 −30,990,229
 Schools −6,217,576 −9,270,271 −3,320,993
 Net Effect 478,270,925 461,307,640 491,141,417

Notes: In each sub-panel labeled “Estimated %Change in average daily consumption” we re-produce the DID estimates reported in Table 3 (approximate %Change in the outcome variable) after taking the transformation, [exp(x)-1] × 100, which allows us here to interpret model estimates in terms of the actual %Change in the outcome variable. In the corresponding sub-panel labeled “Estimated change in water consumption over 30 days (in gallons)” we take each DID estimate and multiply it by the product of: (a) the total number of known properties across each user type; (b) the average number of gallons of water consumed per day over the course of the billing cycle averaged over all properties within each user type; (c) 30 days. This allows us to convert the DID estimates we report into an estimate of the aggregate change in water consumption (in gallons) over the course of 30 days (which is the approximate length of a billing cycle) for each of the four billing cycles following the COVID-19 SAH order.