Project Managers can use a range of tools and techniques to develop, monitor and control project schedules. Increasingly, many of these can be applied digitally (using programs such as Excel, Microsoft Project and so on).
GANTT chart
This is a horizontal bar chart plotted over time (e.g. days, weeks or months). Each activity is shown as a bar (its length based on a time estimate). Depending on task dependencies and resource availability, these bars may be sequential, or run in parallel. Each bar is plotted to start at the earlier possible start date. The plan laid out when the GANTT Chart was created can be compared with actual times taken (plotted below the planned time bars in the chart)
Schedule Network Analysis
The schedule network is a graphical display (from left to right across a page) of all logical interrelationships between elements of work — in chronological order, from initial planning through to project closure. As a project progresses, regular analysis of this network diagram are a check to ensure the project is proceeding ‗on track‘.
Critical Path Method
The critical path of a project is the sequential string of activities that takes the longest time to complete, recognising any dependencies between tasks in this sequence (e.g. one cannot start till another finishes). Arrowed lines represent activities with circles at each end representing milestones (start and finish). The critical path method (CPM) determines by adding the times of all activities on the critical path, the earliest time that the project can be completed
Non-critical activities have an earliest and latest start time (ES and LS, respectively) and an earliest and latest finish time (EF and LF, respectively). The ES and EF are found by working forwards through the project network and the LS and LF by working backwards. The difference between the LF and EF of each activity have zero float; they must be done when planned or the project overall will be delayed.
PERT (Program Evaluation and Review Technique)
PERT charts differ from CPM charts in the way times are calculated for activities. They allow better for uncertainty. For each activity, three estimates of time are obtained: themshortest time (SP), the longest time (LT) and the most likely time (MT). The estimate
assigned for the activity is a weighted average of these three estimates. The formula is:
Expected time = (SP + 4(MT) + LT) /6.
Schedule Compression
A schedule can be shortened two ways:
• crashing: using more resources than planned on the task
• Fast-tracking: adjusting the schedule so, mindful of task dependencies, more activities are done in parallel than was planned
Risk multipliers
This involves building in a time or resource contingency for tasks considered to be at high risk of overrun.
Loading
This is assignment of jobs to process centers. It is the process of assigning work to limited resources, Perform work on most efficient resources and use of assignment method of linear programming to determine allocation
Sequencing
This is determining the order in which jobs will be processed. It involves prioritizing jobs assigned to a resource. If no order specified use first-come first-served (FCFS) Each attempts to achieve to an objective
Sequencing Rules
- FCFS – first-come, first-served
- LCFS – last come, first served
- DDATE – earliest due date
- CUSTPR – highest customer priority
- SETUP – similar required setups
- SLACK – smallest slack
- CR – critical ratio
- SPT – shortest processing time
- LPT – longest processing time
