Scheduling and Monitoring Projects Flashcards
What is the scheduling problem?
Projects tend to be either:
1. Time constrained
- must be completed by fixed end date
- add resources as required to meet the deadline
- focus on resource utilisation (smooth the demand)
- delay non-critical activities by using slack to reduce peak demands and fill troughs in demand
- Resource restrained (people, materials, equipment, cost)
- must be completed with a fixed level or resources
- project may be delayed in order to keep within the resource constraint
- allocate resources so as to minimise project delay without exceeding resource constraints
What impact to constraints have on the project schedule?
- Can delay start or completion of project activities
-Resources can be increased to speed ip activity/ project completion - Delaying or bringing forward activities to optimise use of resources is called either ‘smoothing’ or ‘levelling’ depending on the effect on the critical path
- Shortening the critical path is called ‘CRASHING’ the project
What is the purpose of float (slack)?
- Start/ finish dates for activities can be shifted
- Activities can run concurrently
- Float can be manipulated to optimise project duration AND use of resources (i.e. cost)
What happens when resources are not capable of meeting peak demand requirements and are constrained?
The project manager has to:
- Level resource usage
- Prioritise and allocate resources to minimise project delay
- If resources and people are over-allocated, consider reallocating work activities
- Consider crashing activity times
How do you schedule for efficient resource utilisation?
It is invariably inefficient to always start activities at their ES time:
- causes peaks and troughs in resource usage (people, materials, equipment and working capital)
It is often desirable to ‘level’ or ‘smooth’ resource usage throughout the project:
- sometimes via redrawing of the network
- more likely via adjusting project start, completion, and/ or crashing/ lengthening duration times
What are the activity crash times and costs?
Normal time = realistic, cost-effective, efficient method for completing an activity under normal conditions
Normal cost = the cost of completing the activity in normal time
Crash time = the shortest possible time an activity can be completed if resources are not constrained
Crash cost = the cost of completing the activity in crash time
What is the formula for the Cost Slope?
Cost Slope = (crash cost - normal cost) / (normal time - crash time)
Cost slope = crash cost per day
How do you approach crashing a project?
- Ignore tasks not on the critical path
- Select the critical path task(s) with the lowest crash cost(s) to crash first
What are the options for crashing project activities?
- Adding additional resources
- Outsourcing project work
- Scheduling overtime working
- Establishing a team-concerted effort
- Quick and dirty attempt (sometimes works)
- Fast tracking (concurrent activities)
- Brainstorm time saving ideas (value management)
- Reduce scope of project
- Rephase project delivery (part delivery)
- Compromise quality
POTENTIALLY KEEP GOING UNTIL ALL ACTIVITIES ARE CRITICAL
What can changes to projects arise from?
- Customer request (external)
- Project failures (internal)
- e.g. functional deficiencies, slippage, cost variances
What can the need for recovery action be triggered by?
Adverse variance on a number of measures. e.g.:
- Budgeted costs vs actual costs
- Budgeted man-hours vs actual man-hours
- Budgeted % complete vs actual % complete
- Scheduled date of milestone vs actual date of milestone
What data needs to be monitored?
- Cost data (only available at the end of the accounting period - does not include commitments)
- Man-hours (normally accurate and up-to-date, as time sheets are completed weekly)
- % complete (subjective and optimistic)
- Milestones (accurate but too late for remedial action)
What performance criteria will the project manager need to monitor?
- Time performance
- Cost/ budgetary performance
- Technical and quality performance
All in time to take corrective action
How do you evaluate project progress?
There are different ways to do this, which are often derived from methods of project scheduling:
- the project network (AOA or AON)
- individual reports for WBS work elements or packages (accountability)
- Gantt charts and control charts
Gantt charts and control charts are most usually used for reporting purposes:
- easy to understand
- provide an overview (not overly detailed)
- don’t include connection with cost
