There are four aspects to Project Time:
Activity Duration Estimating
Bar or Gantt chart
Activity Duration Estimating
Once having defined the activities or tasks you must decide how long each task will take
before they can be arranged in sequence.
Duration and Effort
There are two kinds of time commitment for each of the activities of a project.
Duration is the amount of time from the beginning of the activity to its
completion. Duration has a direct effect on the schedule.
Effort or resource time is the amount of time required for the people to complete
it. Effort is directly related to the cost of the time expended on the project.
Duration and effort are not usually the same. For instance an approval may take three
weeks from start to finish, giving it a duration of three weeks, but it might only take one
or two hours of your own time, leaving you free to do other things. On the other hand a
task might involve three people for three weeks. In which case the duration is three
weeks but the effort is equal to nine weeks.
All estimates are just that - informed guesses about how long a particular task will
take to complete. In the project risk template note down any risks associated
with the estimates of duration you have made.
When estimating the duration of an activity or task consider:
Part-time working on a project
Time lost and interference from non-project activities
Skill and experience of the people who will be doing the task
Priority of the project - will other activities take precedence if time is short?
Availability of staff with special skills
Be realistic with your estimates - don't massage estimates to suit unrealistic
deadlines. A project that is manipulated to meet an unrealistic timeframe will
The linked Activity Durations template might be of assistance.
Using the activities and the durations we can now place them in sequence and develop
the Schedule for the project.
The schedule allows progress of the project to be assessed, communicated and
coordinated and it identifies key milestone dates to be met.
Some tasks can be done at the same time. Others will be dependent upon previous
tasks being finished.
The "sticky" note method:
Particularly early in the project agreement, "buy-in" and the advantages to be gained
from expert opinion is best obtained through involvement of the key stakeholders in
developing the initial schedule. Simply ask the participants to arrange the sticky
notes from the Work Breakdown Structure in order of sequence. Then draw arrows
between the sticky notes to indicate the order of events andthe dependencies.
The diagram above for the first phase of a staff survey project is called a
Precedence Network because it describes the dependencies between activities
The pathway through the sequence in which the total of the durations is greatest is
called the CRITICAL PATH. It indicates the minimum total time from start to finish of
the project or phase.
In the example above, the CRITICAL PATH runs through the following activities 'identify questions' - 'obtain approval' - 'conduct initial interviews' - 'refine survey'
because this pathway is the longest total duration.
The total length of the critical path is 27 working days. That is, the project will take a
minimum of 27 working days from start to finish. The activities - 'literature search' and
'define focus groups' are not on the critical path. They can be done in parallel with
There are always risks associated with a network or schedule. The most influential
risks in terms of the schedule tend to be those on the critical path. For example a
risk could be associated with the activity 'obtain approval', especially if the approval
requires sign-off by senior managers. If the duration has not been estimated
correctly the initial interviews would have to be delayed. Often it is difficult to get
focus groups together. This could constitute a major delay to the entire project.
You should enter any risks associated with the schedule in the Project Risktemplate.
Reducing time to completion - shortening the critical path:
If your network calculations do not meet the scheduled completion date for the project,
as per the project objectives, the critical path might need to be shortened. This can be
done by adding resources, which will allow activities to be completed in a shorter
duration, or certain activities might be undertaken at the same time, or in parallel. It is
not good practice, and is particularly unfair to project personnel, to "massage" activities
into unrealistic timeframes!
This tool is used to indicate key dates. Milestones are either set for the projects or
established by the project team as dates to be met. Milestones might indicate the key
dates to be met during the execution of the project, such as a report to a board
Generally milestone plans are effective communication tools. They can be used to
create a sense of urgency and to reinforce with key stakeholders and the project team
the key dates in the program to be achieved.
Milestone plans are not used as planning tools unless the project manager is
extremely familiar with the type of project or the project is a "fuzzy" project
which must be planned step by step.
An example of a Milestone Plan for a training session is shown below:
The milestones are commonly included in the Project Proposal document.
Bar or Gantt chart
This tool is one of the most easily understood of the schedule formats. It lists the tasks
with a task bar next to each task showing its time duration.
The project schedule is commonly presented as a Gantt chart. It is an excellent
communication tool, however, as the Gantt chart does not show dependencies very
clearly it is less easily manipulated than the precedence network.
Milestones (traditionally represented by a diamond shape) can be plotted on the bar or
Gantt chart for easy reference to key dates in the schedule.
Beware too much technology too soon in the process!
In recent years the use of computer enhanced scheduling systems has meant that the
production of the schedule has become a solitary activity.
It is strongly advised that the initial schedule be created as a "group activity" otherwise
there are risks of insufficient commitment by key stakeholders to the durations and
dependencies and lack of expert information at a key stage in the planning process.
Once the key stakeholders and project team have ownership, the schedule can be
converted using an appropriate computer based scheduling program.
It is unlikely that one person (the scheduler) will have expert knowledge of
every task in the project!