gantt charts

Gantt charts.
The PERT chart is an excellent start point for the production of a bar chart or Gantt chart which is required in order to clearly show the start and finish dates for the major activities. Gantt Charts - named after their founder Henry Gantt, are the preferred information media of senior managers, who usually find that the information portrayed in PERT charts is too detailed. Gantt charts are simple to understand and easy to change, however they only provide a vague description of how the whole project is reacting as a system. Modern software planning packages are able to present the project data in a wide variety of formats including numerical sequence, alphabetical and date order. When producing Gantt charts; care should be taken that each distinct area is clearly definable - by applying an appropriate color or shading regime.

Gantt Chart Limitations.
The Gantt chart has three significant limitations. Firstly, the sequencing and inter-relationships between the activities are not shown, therefore they do not represent a
network of the activities. If one activity is accelerated or delayed it will be difficult to see the effect that this may have on associated activities.
Secondly, the Gantt chart cannot show the results of either an early or a late start in the activities. It does not reflect true project status because elements behind schedule do not mean that the project is behind schedule. Finally the Gantt chart does not show the uncertainty involved in performing the activity, therefore questions concerning the minimum or maximum duration of the activity are not represented.

Logical Bar Chart.
The logical bar-chart shows the logical relationships between the activities. Whilst this technique is useful, be aware that on larger projects the volume of activities may result in a cluttered presentation. Many variations of Gantt chart can be used to represent a broad spectrum of project information and in spite of its limitations the Gantt chart remains the most common presentation format for senior management.

Histograms & Pie Charts.
Project management staff need to calculate how many resources a specific activity will require. They also need to establish the overall resource requirements of the project, for any given period - possibly including the resources needed on a daily basis. The type of diagram that facilitates this is called a histogram (or bar chart) and is another widely used project planning aid. Histograms enable this information to be portrayed clearly. They can be derived from the Gantt chart representing the period in question. The only additional information that may be required is the type of specialist resource required for each activity. The pie chart is another useful method of presenting summarized project information. The resulting diagram, which again exploits a color or shading key, is easy to generate and understand. The major drawback with pie chart presentations is that they do not permit comparisons as readily as bar-charts, where estimated and actual figures can be represented as two colors within the same bar.

Optimizing Project Resources.
In project management terms all of the staffing requirements, money and physical objects that the project will consume or require are termed resources. Resource planning aims to ensure that the project is run efficiently, by keeping all the dedicated project resources as fully utilized as possible. It also aims to facilitate the accurate prediction of the demands that will be placed on the project and enables the identification of important issues such as potential bottlenecks. Resource planning is concerned with the effective scheduling of skills, experience, financial and technical resources necessary in order to deliver the products required. It is crucial to the success of the project and the work involved grows rapidly in complexity as the number of individuals and the required skills increase. Resource planning should be an iterative process, helping to refine the PERT chart by optimizing the use of resources throughout the project life cycle.

Product Based Planning.
The overall planning process involves a number of iterative steps beginning with the identification of the products that are required to deliver the overall end-product. This should be followed by identification of the resources needed and the sequencing of the activities required. The PERT chart should be updated to reflect the resources and activities as they are identified. This is followed by assigning the activities and responsibilities to suitably qualified staff. With the shape and size of the project now visible, the total cost of staff and other resources for each planning period can now be calculated. Costs should be itemized by resource type, identifying the number of staff at each skill, or cost, level. Up to this point the planning process would normally have assumed one-hundred percent availability of staff to work on project related tasks. Thus a full-time person is scheduled for five full days each week - in reality, they may not be available on this basis. Furthermore, this type of planning takes no account of non-productive time due to things such as unscheduled meetings, unrelated work tasks, coffee breaks etcetera. In practice, planners should also make allowances for holidays and contingency for sickness leave.

Defining the Resources.
Resources can be broadly divided into consumables and non-consumables. A consumable resource is consumed as it goes into a task, for example, when money is spent on paying contractors it cannot be used again. Non-consumable resources can be used over and over again - manpower and equipment used on a project are obvious examples of non-consumable resources. It is often helpful to consider resource definitions, in order to define the capabilities, cost and productivity of different worker groups. This classification is normally conducted with reference to the skill profiles of staff. It is important to define the effort that each group can produce per unit of time in order to accurately match the task needs with the allocated resources. The various resource definitions may be supported by estimates of the quantity of each resource that will be available throughout the projects life cycle. This information is called a resource availability profile and these are often shown as graphs of the level of availability against time.

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