CRITICAL PATH ANALYSIS

Critical Path Analysis

Critical Path Analysis

Critical path analysis (CPA) is a mathematical procedure that calculates a project's schedule. Taking each task in turn it firstly calculates how quickly the task can be accomplished these dates have been calculated, the determined. With this finish date known, CPA can then c each task can be accomplished (information is known for each task, CPA will also calculate that the task possesses).

Take the network of tasks and list the task's name and duration:

Calculating early dates for tasks

Early start and early finish dates for tasks are calculated by a process known as a forward pass. This proceeds through the project's network from the earliest occurring tasks (positioned to the left side of the diagram) to the latest occurring tasks (positioned to the right side of the diagram).

a. Enter an ES value of 0 for any task that has no predecessor (as it can commence straight away).

b. For each of the tasks with ES=0 values, their EF value will be calculated from the ES value PLUS the task's duration (for example; 'Design Structure' will have ES=0 and EF=5 (day number 5 of the project)).

c. As 'Write body text' and 'Create exercises' have a common predecessor, the ES value for BOTH of them will be the same as the EF value for their common predecessor; day 5.

d. The EF for 'Write body text' is calculated by ADDING the duration value (in this case 15 days) to the tasks ES value (day 5), thus finishing on day 20.

e. The EF for 'Create exercises' is calculated as operation four, with EF = ES+Duration (5+10 = day 15).

f. 'Set page layouts' can commence as soon as its predecessor is complete; day 20.

g. 'Test exercises' can commence once its predecessor is complete; day 15.

h. EF values for 'Set page layouts' & 'Test exercises' can be calculated as EF = ES+Duration (days 25 and 20 respectively).

i. As 'Create contents and index' has multiple predecessors, it can only commence when ALL of them are complete. Its ES value is therefore day 25 (the EF of its LATEST predecessor).

j. The EF for 'Create contents and index' is simply ES+Duration - day 30. The project finish date is therefore day 30.

The calculated diagram would look like this:

Earned Value Analysis

Figure 1-Typical Curve Showing PV, EV and AC

Planned Value (PV) is the budgeted cost for the work scheduled to be done. This is the portion of the project budget planned to be spent at any given point in time. This is also known as the budgeted cost of Work scheduled (BCWS).

Actual Costs (AC) is simply the money spent for the work accomplished. This is also known as the actual cost of work performed (ACWP).

Earned Value (EV) is the percent of the total budget actually completed at a point in time. This is also known as the budgeted cost of work performed (BCWP). EV is calculated by multiplying the budget for an activity by the percent progress for that activity:

EV = % complete x budget

For example, if a ...