100-Metodos-de-Qualidade-Total

ANALYTICAL METHODS
81
Method 33
Critical path analysis (CPA)
Purpose
A project planning technique which separates the work to be done into
discrete elements, allowing the key elements that affect the overall project
to be identified.
When to use
At the project design stage and then at all subsequent major project
revIews.
How to use
CPA is a very simple process but it can be very time-consuming. To
overcome this, there are many software packages available to carry out the
computations. Each is different but the basic steps are the same.
1 Brainstorm all of the activities to be carried out and label them.
2 For each activity, record any constraints such as time or order.
3 Draw the flowchart of the activities in time order.
4 Estimate the time for each activity and insert these times in brackets on
the appropriate labelled brackets of the network.
S
Using the available software, calculate the critical path and the idle (or
float) time left. If the critical path indicates that the project is not
possible in the time available, re-examine the assumptions made and
modify the finish date if necessary.
6 Monitor progress, recalculating at each review stage, since the changes
caused by actual performance can change the critical path.
Benefits
CPA allows the effects of different courses of action to be determined at
the planning stage, allowing the best overall approach to be decided.
Example
Smartware Systems Ltd is designing and installing a computer system for a
client in the brewing industry. The tasks involved and the estimated duration,
together with details of preceding activities which must be completed before