Gantt Chart Scheduling
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Abstract
Gantt Charts are the foundation of planning and scheduling, thus perhaps being the most important element in project management. The Gantt Chart is a tool that allows managers to boil project parts and phases down to simple visual blocks based on the planned and expected duration, which can then be arranged according to interdependencies. Furthermore, as a visualisation tool, it provides overview of planned processes, in order for managers or stakeholders to keep track of what progress should be obtained at a certain point in a project.
This article sheds light on the overall concept of Gantt Charts, what they are used for and the relation to project management. As Gantt Charts are an almost inevitable scheduling tool when managing projects, it is also a key scheduling tool when using both the project management standard of the Project Management Institute[1] and Prince2[2].
As Gantt Chart Scheduling is a tool, the article suggests a guide of what to consider when using the tool, as well as how to apply it. The article suggests five key elements of Gantt Chart Scheduling, Scaling, Timeframe, Activities, Estimation, Relations. The Scaling element addresses who are using the Gantt Chart and the purpose of using it, in order to frame the scaling of the tool. The Timeframe is a step of considering the project timeline, whereas Activities represent the activities of the project, which are to be scheduled using the chart. The fourth element is estimating duration of the activities, followed by the Relations where interdependencies between activities are identified.
Gantt Charts are somewhat limitless with regards to the sizing and extent of the application, however, the chart itself does not solve scheduling issues. The article therefore addresses the limitations of Gantt Charts and challenges that may occur when applying them, as well as opportunities that stems from them.
Overall Concept
The Gantt Chart was developed by Henry L. Gantt in the 1910s and the overall concept is to provide a visual overview of time, tasks and progress within a process consisting of a collection of activities. [3] Furthermore, the Gantt Chart is a tool to manage activities in relation to each other, in order to achieve a certain goal within a timeframe. Thereby Gantt Charts can be used as a tool for managing complexity in projects by scheduling project activities.
A Gantt Chart is a dynamic diagram that visualises scheduling of activities. The core elements of the Gantt Chart are horizontal bars representing activities of a given project. The length of the bars can represent the duration of the activity and the bars are placed according to their earliest possible start within the timeframe of the project. The earliest possible start of an activity is determined by its contingent relations to other activities. As Gantt Charts are a tool for managing activities, it is crucial to actively update the chart with real-time data, in order for activity progress or delay to be considered in the progress of related activities. If the chart is not updated accordingly, it simply shows an instant snapshot of the situation and progress of the project, at the time of creation.
The following figure shows an example of a basic setup of a Gantt Chart. The vertical axis consists of activities A-E, whereas the horizontal axis shows the timeline in an unspecified measure of time from 1-10. Furthermore, the purple boxes in each row indicates the scheduled start time, end time, duration and relation between the activities.
Gantt Charts are particularly useful in project management when managing time schedules and project activities. The British project management standard Prince2, suggests the use of Gantt Charts to present project schedules as well as an active stage plan. Furthermore, the standard encourages project managers to develop Gantt Charts for both the project plan and the team plan in order to respectively establish a tool for project control and assigning of deliveries.[2] Also the Project Management Institute suggests Gantt Charts as the tool for scheduling as well as project governance in their Guide to Project Management.[1]
Gantt Chart as a tool
The following section describes how you as a project manager can create and use a Gantt Chart. In order to use Gantt Charts, there are several perspectives to consider. The core of the method can however be boiled down to the following five elements:
- Scaling
- Timeframe
- Activities
- Estimation
- Relations
Each of the elements are described in the following sections. Furthermore, their relevans to project management is addressed as well as how to consider and apply them in project management.
Scaling
The first step of creating Gantt Charts is to consider its recipients and purpose, in order to determine the frame; both a visual frame for your chart and for you to scale the content. Therefore, you need to consider in what setting the tool is applied. The setting in which you are applying the tool impacts, how you should present the Gantt Chart. Is it for example only for personal use in a private setting, you might be able to settle on simplicity in your Gantt Chart; perhaps a drawn up version on paper or a spreadsheet.
However, if you on other hand are using the Gantt Chart in a professional setting, you ought to consider who is going to see, use and manage the chart. Are you for example using it in workshop with the project team? Then it might be useful to draw up the chart on board or a Flipchart, using post-its as activity blocks, that can be moved around throughout the workshop.
The chart might also be used actively throughout the lifetime of a project by several members of the Project Team. In that case, you ought consider where to place the chart, which will then impact the format. It might need to be placed on a company server or a joint platform, where all team members can access, edit and update the chart. In this case, the format could be a spreadsheet or perhaps even a dedicated project management software.
Furthermore, the chart might also be used as visualisation tool for the steering committee, project sponsors or other internal and external stakeholders. In that case presentation and clarity is crucial, as stakeholders outside the project team, might not have the necessary insights to understand the individual activities. Therefore, it must be considered how to present the chart to stakeholders, including clarify stakeholder expectations with regards to reporting and governance.
Overall you, as a project manager or simply user of a Gantt Chart, need to consider the purpose of the Gantt Chart, hence defining the setting. Furthermore, you must consider, who are the users of the chart and recipients of any information gained through the chart. These perspectives should give you an idea of where and how to develop and structure you Gantt Chart, by scaling the level of detail.
DTU Example
In order to show an example of how to scale a Gantt Chart with regards to a project, we consider an example of a project represented by the development and completion of a study and its deliverables for a university course at DTU.
The setting is the frame of the course, hence the creators of the chart is a group of students, that must work on a project throughout the course and finally deliver a report. The group is considered the project team and they will use the Gantt Chart to delegate assignments, represented as activities, and to estimate when to initiate the different activities in order to deliver the expected and required deliverables on time.
As the team members do not necessarily see and speak to each other on a daily basis, they decide to use a platform like Microsoft Teams, to store the Gantt Chart in a spreadsheet. On the platform all team members can access and edit the chart, so they are updated in between meetings. Furthermore, as the team is cooperating with an external company, they use the spreadsheet as a visualisation and governance tool of their progress, when meeting with their stakeholders, such as the company, teaching assistants and in course presentations.
Timeframe
Secondly, time must be considered; are you scheduling a project with a specific timeframe? A programme covering several projects which might be extended further when introducing new projects or perhaps a portfolio linked to a long term strategy or vision of an organisation?
Projects are usually time boxed early in the scoping phase, as the steering committee matches expectations of project completion and demands from project sponsors. The Gantt Chart is then time bound to the start date and end date of the project. When considering the programmes, the timeframe can be fluid as the content of the programme can be extended with additional projects, hence often pushing the programme end date. Thereby the Gantt Chart does not end until the programme is considered to be closed. The same is applicable to Portfolios, which with regards to scheduling, has a more undefinable end date.
Application – Timeframe
Once you have determined the purpose of the Gantt Chart, the time can be considered. Defining the timeframe of the Gantt Chart can be done simply by determining the start and end date, if such exists. This of course depends on the scale and purpose of the chart, which has been determined in the previous step.
DTU Example
When considering the DTU course deliverable example, the timeframe of the project is limited to the time between the start of the course end the examination or hand-in date. At DTU, this could be a spring course running from the beginning of february to mid may, covering 13 course weeks plus contingent holidays and vacation weeks within the period.
Activities
As the Gantt Chart is a way of structuring and scheduling tasks in relation to each other, the planner must identify and define activities. Within Project Management this is usually done in the scoping phase of the project, where for example a Work Breakdown Structure can be used to break down the project objective to doable activities or solvable tasks.
In programme management, the Gantt Chart activities can consist of grouped tasks within a project, thus for example representing activities or deliverables of work breakdown structures from the different projects. When considering Gantt Chart activities in Portfolio Management, these might consist of entire projects or perhaps large deliverables of the different projects.
Application – Activities
In order to define activities in the Gantt Chart, several different approaches can be applied. As mentioned in the description of Activities, it all comes down to the purpose, usage and scale of the chart, which was defined in step 1.
In general, a Work Breakdown Structure is a useful tool, when defining activities. In your Gantt Chart, you want to add tasks that are applicable to the recipients of the chart, thus using the Work Breakdown Structure, to define suitable activities. For projects you want activities suitable for the project team members, whereas Gantt Charts for programmes should include activities leading up to major milestones in the different projects of the programme, hence applying to project managers. When using Gantt Charts for Portfolios, the activities could consist of entire projects and programmes, hence describing activities for project and programme managers.
DTU Example
In the example of considering a course deliverable as project, the activities on a stakeholder management level could consist of for example Research, Collecting Data, Data Processing, Assessing results, Solutions design and reporting. Furthermore, the activities could be split into well-defined tasks to meet the purpose of delegating work to group members and managing the progress. For example, the research activity could be broken down into tasks of identifying, evaluating and sorting existing research, whereas the data collecting activity could have a task of making a survey, conducting the survey, a field observation study, collect quantitive dataset from a stakeholder amongst others. Thereby the Gantt Chart can both accommodate the needs of the group and the stakeholders.
Estimation & time
In order to schedule the activities, a timespan or duration must be assigned to the activities. With regards to project management, duration is often the result of an estimation based on actual experience of project organisation members or organisational experience and data from previous comparable tasks. When considering Programmes and Portfolios, the time estimation is limited to the estimated duration of larger deliverables or entire projects.
Furthermore, the duration estimation must determine the time unit type; will the terminology be based on days, weeks or perhaps months? This is also impacted by whether the chart covers project, programme or portfolio management, as well as the overall duration and the level of detail of the activities.
Application – Estimation & Time
Duration estimation of activities should be done
DTU Example
Considering the identified tasks and activities, the group members will use their experience from previous courses to estimate, how much time each activity and tasks should be assigned. This could lead to the task of creating a survey being estimated to one week whereas the actual survey conduction could be estimated to two weeks, and so on.
Relations
The last yet very important element of Gantt Chart Scheduling is the relation between activities. A relation exists if a task cannot for example be commenced or finished before or until another specific task has been fulfilled. This is the essence of Gantt Chart Scheduling, as the relations determines when the different activities can be conducted, hence controlling the time of the final delivery and the overall duration.
Furthermore, external factors can have an impact on the commencement, fulfilment and duration of activities. An example of an external factor is weather or temperature, which could dictate that a project should be conducted at a certain time of year. Furthermore, also politics, legislation, funding, global or national crisis amongst others, can have an impact on the relations between activities as well as progress.
Application – Estimation & Time
- Experience - Work Breakdown Structure o Arrange in hierarchy What comes first?
DTU Example
The DTU group will find that the activity of conducting their survey cannot be performed until the survey is actually developed. Therefore, the actual conduction is dependent on the survey being created, thus the two activities are related. Furthermore, the Covid-19 Pandemic of 2021, is causing the group to extend the duration of their field study due to crowd restrictions.
Introduction: Gantt Charts can contain many different features, depending on whether a software is used, Excel or just a flipchart with post its
Step by step – what to put where
Additional features depending on level of detail: - Milestones o Important dates or deliverables - Automation o If in spreadsheet add: Scheduled start time Scheduled duration Actual start time Actual duration - KPIs and analytics o Use knowledge to
What next? - Now its created - When do I look at it again o Depending on scale and time description - When to react? o But in KPIs Start on time End on time Late start • Reflect to Critical path
Limitations
Who, Where and When
If you do not update, then it just shows where you left it. It is not automized – can however be automized, in some cases
Annotated bibliography
1. In Prince2 2. In PMI 3. In Large Scale Projects 4. In Excel
