A project is represented by the activity durations (estimated at 90% likelihood of completion)and precedence requirements shown in the table.What is the length of the project buffer if this project is managed using critical chain methodology? $$\begin{array} { | l | l | l | l | l | l | }
\hline \text { Activity } & \text { Predecessor } & \text { Length } & \text { Activity } & \text { Predecessor } & \text { Length } \
\hline \mathrm { M } & - - & 8 & \mathbb { R } & - & 12 \
\hline \mathbb { N } & - - & 8 & \mathrm {~S} & \mathrm { P } & 14 \
\hline \mathbb { P } & \mathbb { M } & 12 & \mathrm {~T} & \mathrm { R } , \mathrm { Q } & 7 \
\hline \mathrm { Q } & \mathbb { N } & 10 & \mathrm {~V} & \mathrm {~S} , \mathrm {~T} & 11 \
\hline
\end{array}$$
A) 13.5
B) 22.5
C) 11.25
D) 9.0

Question

A project is represented by the activity durations (estimated at 90% likelihood of completion)and precedence requirements shown in the table.What is the length of the project buffer if this project is managed using critical chain methodology? $$\begin{array} { | l | l | l | l | l | l | } 
\hline \text { Activity } & \text { Predecessor } & \text { Length } & \text { Activity } & \text { Predecessor } & \text { Length } \
\hline \mathrm { M } & - - & 8 & \mathbb { R } & - & 12 \
\hline \mathbb { N } & - - & 8 & \mathrm {~S} & \mathrm { P } & 14 \
\hline \mathbb { P } & \mathbb { M } & 12 & \mathrm {~T} & \mathrm { R } , \mathrm { Q } & 7 \
\hline \mathrm { Q } & \mathbb { N } & 10 & \mathrm {~V} & \mathrm {~S} , \mathrm {~T} & 11 \
\hline
\end{array}$$
A) 13.5
B) 22.5
C) 11.25
D) 9.0

Quizplus · Accepted Answer

The project buffer in critical chain methodology is typically half of the total safety time removed from the original schedule. The safety time is the difference between the 90% likely duration and the 50% likely duration. Assuming the 50% likely duration is about 50% of the 90% likely duration, the buffer is calculated as half of the total safety time.

A Project Is Represented by the Activity Durations (Estimated at 90