Causes, Effects, and Mitigation Measures of Time and Cost Overruns in Water Supply Projects: Case of Tigrai Region, Northern Ethiopia

Table 6

Linear regression for time overrun and model parameter estimates. Regression model: Log (time overrun) = β₀ + β₁  Der + β₂  Lcs + β₃  Cho + β₄  Dmi.

Predictor variable	Parameter estimate
Constant, β0	1.658^a
Design errors and changes (Der), (days), β1	0.005^a
Inconsistency between bill of quantity and drawings (Lcs), (days), β2	—
Change order (Cho), (days), β3	0.06
Delays in material import (Dmi), (days), β4	0.004^a
r^2

Note: ^aParameter estimate significance (). Model fit significance ().