Schedule Updating and Project Control - Construction Project Scheduling and Control - page 186

example, a contractor is installing 25 doors. Four doors that have not yet been
started are 0% complete. Eight doors have had their frames erected. They are
considered 30% complete. Another six doors have been hung. They are said
to be 50% complete. Four more doors have been painted, making them 75%
complete. The last three doors have had the hardware installed. They are now
100% complete. Each door goes through the stages for installation, shown in
the following chart:

Task Weight (%) Cumulative Weight (%) No. Units % Complete Weight

Notyetstarted 0% 0% 4 4*0%/25 = 0.0

Erect door frame 30% 30% 8 8 * 30%/25 = 0.096

Hang door 20% 50% 6 6 * 50%/25 = 0.120

Paint door 25% 75% 4 4 * 75%/25 = 0.120

Install hardware 25% 100% 3 3 * 100%/25 = 0.120

25 Total = 0.456 = 45.6%

6. Weighted or equivalent units: The weighted or equivalent units method is used
for large and complicated activities that usually comprise several consecutive
or overlapping subactivities. The method involves the following five steps:

a. Assign a weight to each subactivity so that total weight = 100%.
b. Multiply the weight of each subactivity by the quantity of the total activity.
This is the “equivalent weight” in units for each subactivity.
c. Determine the percent complete for each subactivity by using one of the
previously discussed methods.
d. Multiply the percent complete for each subactivity by its equivalent weight.
The result is the “earned quantity.”
e. Add earned quantities for all activities and divide by total quantity.

This is the percent complete for the total activity. For example, for a
wall-framing activity, with a total quantity of 3.5 MBF (1,000 board-feet),
the information shown in the chart may be true:

Unit a Assigned

Weight

Subactivity Total

Quantity

Equivalent
MBF

Completed
Quantity

Earned
MBF

0.04 Bottom Plates EA 20 0.14 20 0.14

0.40 Studs EA 320 1.40 210 0.92

0.08 Corners EA 12 0.28 8 0.19

0.12 Blocking EA 160 0.42 92 0.24

0.14 Door Openings EA 10 0.49 5 0.25

0.16 Window Openings EA 12 0.56 5 0.23

0.06 Top Plates EA 40 0.21 0 0.00

1.00 Total MBF 3.50 1.97

a EA = each.

Percent complete = 197∕3 . 50 = 56 . 3%