Variations in construction quantities are obvious measures of the accuracy of estimates of those quantities. QEI is computed as 1.00 minus the quotient of quantity variations divided by the low bid price. Quantity variations are computed as the sum of the absolute differences between the final costs and bid amounts for all unit-priced items. CDQI is computed as the sum of the weighted values of the individual indexes. Quality designs reduce bidders' risks.
Lower risks induce smaller variations among bids.
D-REWI is ranked second in its weighting influence because, on its face, construction extra work that has been caused by design shortcomings is a clear indicator of failures in design quality. CPEI and SPI are equally weighted as predictors of design quality. Designs that produce satisfactory deliverables on schedule are likely to have fewer problems during construction. Designs that are not timely or are poorly rated by sponsoring organizations are precursors of construction problems. QEI measures only the quality of the sponsors' office estimate.