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. 2016 Dec 7;2(2):e169. doi: 10.2196/publichealth.3381

Table 4.

Difference in differences (DID) estimates: impact of calls on performance indicators in the intervention and postintervention stages.

Dependent variable Case activity Form submissions (number) Duration of counseling

DID t (df) P DID t (df) P DID t (df) P
Original sample (n=500)

Treatment –3.98 –0.57
(499)
.57 –7.09 –0.95
(499)
.34 –0.54 –0.32
(499)
.75

After 9.07 2.65
(499)
.008 –32.32 8.20
(499)
.001 0.57 0.77
(499)
.44

Treatment×after 5.58 0.98
(499)
.33 2.032 0.29
(499)
.77 4.78 3.66
(499)
.001

Constant 22.20 5.34
(499)
.001 52.15 12.31
(499)
.001 2.43 2.54
(499)
.01
Correcting for attrition (n=600)

Treatment –6.06 –1.40
(599)
.16 –1.142 –0.29
(599)
.77 –0.64 –0.42
(599)
.67

After 12.71 4.52
(599)
.001 –25.36 –7.77
(599)
.001 0.746 1.09
(599)
.27

Treatment×after 4.45 1.2
(599)
.023 –1.39 –0.37
(599)
.71 4.34 3.65
(599)
.001

Constant 21.43 5.18
(599)
.001 44.51 10.7
(599)
.001 2.31 2.62
(599)
.009