Effective Sequence Planning And Time Scheduling For Projects
 

Effective Sequence Planning And Time Scheduling For Projects

January 28, 2010 Email This Post Email This Post Print This Post Print This Post

In the previous articles you’ve learnt something about the nature of projects and the management of them.

I’ve told you that a project is always located in 3 dimensions: quality, resources and time.

The project structure plan tells you what has to be done in your project in form of work packages. It defines the quality which means the content of your project.

The project structure plan is also the basis for further necessary plannings because obviously it is not enough to have an idea about just the quality of your work packages.

It’s essential to analyze the duration of the work packages and the sequence in which they have to be executed in order to be able to calculate the corresponding start and end dates.

This step requires a mergence of the 3 dimensions quality, resources and time. Sequence planning and time scheduling represent such a mergence.

These plannings help you to plan, to monitor and to control dates and the degree of achievement of your work packages which are called actions or activities within such a planning.

Together sequence planning and time scheduling build an early warning system for project managers by helping them to avoid delays.

Delays require high efforts to regain lost time and lead to problems and further delays in the following work packages.

Please keep in mind: Delays always generate costs.

There exist various tools to visualize an integrated sequence planning and time scheduling. They differ from each other in the level of detail and consideration of dependencies between the different work packages:

  1. Bar Diagrams (Gantt Charts)
  2. Network Diagrams
  3. Networked Bar Diagrams (Compromise)


In the following paragraphs you can find a brief desctiption of these tools by mentioning some advantages and disadvantages:

Bar Diagrams (Gantt Charts)

This type of chart was first developed by Henry Gantt.

A Gantt chart is a type of bar diagram that illustrates a project schedule. Gantt charts illustrate the start and finish dates of the work packages of a project.

bar_diagram

Gantt charts can be used to show current schedule status using percent-complete shadings. They visualize the start and end dates of your work packages as well as the duration and responsibility.

Although now regarded as a common charting technique, Gantt charts were considered revolutionary when they were introduced.

Gantt charts have become a common technique for representing the phases and activities of a project.

Advantages

  • Easy to generate (low efforts)
  • Clearly arranged
  • Comprehensible without specific knowledge about Gantt charts
  • Many good software programs available

Disadvantages

  • Dependencies should be obvious and clear
  • Not suitable for complex projects (too little information)
  • No information about the critical path
  • No visualization of time-critical activities

The dependencies between your work packages are normally not automated. This means your changings have to be entered manually.

Although project management software can show schedule dependencies as lines between activities (networked bar diagrams), displaying a large number of dependencies may result in a cluttered or unreadable chart.

Network Diagrams

A project network is a graph (flow chart) depicting the sequence in which the project’s work packages are to be completed by showing work packages and their dependencies.

These diagrams comprehend and visualize the earliest and latest start and end dates, durations and responsibilities of your work packages.

network_diagram

Based upon the earliest and latest start and end dates, a corresponding software is able to calculate buffer times, start and end date of the project as well as the critical path of your project.

The critical path represents a series of work packages that directly influences the end date of the project. A delay of one of these work packages would lead to a delay of the whole project.

A network diagram visualizes the whole project including important information about each work package and including the dependencies between the work packages.

Advantages

  • Recognition of time-critical activities
  • Visualization of complex interdependencies
  • Visualization ot the critical path
  • Applicable for complex projects (> 30 work packages)
  • Automated calculation of time buffers and dates

Disadvantages

  • Relatively high efforts
  • Sometimes they appear abstract and confusing
  • Specific knowledge about network diagrams and their methodology required


Networked Bar Diagrams

Some Gantt charts also show the dependency (i.e, precedence network) relationships between activities (as shown in the image above).

They are called networked bar diagrams.

Networked bar diagrams are a compromise between bar diagrams and network diagrams. They integrate the advantages and compensate some of the disadvantages of both diagrams.

A networked bar diagram is based upon a normal Gantt-Diagramm and is augmented by the definition of automated dependencies. These definitions allow software programs to make various calculations (buffer times, critical path etc.) while presenting them in a clear and well-designed form.

All tools have something in common independent from the sort of visualization:


Milestone Technique

The more complex a project is the more confusing a corresponding visualization becomes. It is helpful to define phases that give your planning a rough order.

You can achieve this by applying the milestone technique.

A milestone is set after a series of work packages that belong together in some kind
(marked with a rhomb in the Gantt chart above)

You should have achieved a noticeable progress after having executed these packages. This technique allows you to break a network diagram of 30 activities down into 4 or 5 different essential phases which are assigned to 4 or 5 milestones.

The data of milestone plans, Gantt diagrams or networked bar diagrams can be the result of the network plan calculation with a network diagram as basis.

But they can also be own discrete forms of planning.

The choice of a planning tool should always consider the complexity of the project as well as its importance for your organization or you personally.

This certainly requires a continous weighting of the expected efforts and benefits.

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