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

Table 7

Linear regression for cost overrun and model parameter estimates regression model: cost overrun = β₀ + β₁  Der + β₂  Lcs + β₃  Inc + β₄  Cho.

Predictor variable	Parameter estimate
Constant, β0	0.015
Design errors and change (Der), (millions), β1	1.054^a
Inconsistency between bill of quantity and drawings (Lcs), (millions), β2	1.136^a
Inconsistency of price of materials (Inc), (millions), β3	1.316^a
Change order (Cho), (millions), β4	—
r^2

Note: ^aParameter estimate significance (); model fit significance ().