## Forming a schedule - Critical Path Analysis

The process of allocating activities to workers for completion, within all of the constraints of the project, is known as scheduling.

We assume:

Procedure:

The information regarding earliest and latest times for each activity is crucial when constructing a schedule. This information may be presented as a table or as a chart.

The

Float = latest finish time – earliest start – duration

Previous precedence network:

We assume:

- Each activity requires 1 worker (unless specified)
- No worker may remain idle if there is an activity to start
- A worker must continue with an activity once started

Procedure:

- When a worker completes an activity, consider all activities which can be started
- Assign the activity with the smallest finish time
- If no activities can be started, wait

The information regarding earliest and latest times for each activity is crucial when constructing a schedule. This information may be presented as a table or as a chart.

The

**float**for each activity must be considered. The**total float of an activity**is the maximum time that the activity may be delayed without affecting the overall time of the critical path, and thus the completion of the project. The total float for an activity may be divided into independent float and interfering float.Float = latest finish time – earliest start – duration

**Example:**Previous precedence network:

Remember – critical activities have zero float. This means our critical activities are A, C, E and H; our critical path is ACEH, and the time taken is 15 units of time.

*What happens if an activity needs more than one worker? What if we need to complete the project in a given smaller time? What if we are given an exact number of workers, and need to calculate the exact time to complete the project?*We use scheduling to determine this. See the ‘scheduling charts’ section.