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 address its recipients and purpose, in order to create a frame; both a visual frame for your chart and for you to scale the content. The following questions will assist you in defining the frame for the usage of your Gantt Chart, though you may need to adjust them to your specific situation:
-Are you using the tool for project, programme or portfolio management? Or perhaps other. -Are you applying the tool in a professional or personal setting? -Are you applying the tool by yourself or perhaps in a workshop with team members, internal or external stakeholders? -Will you use the chart to visualize progress for stakeholders?
What is your role as creator of the Gantt Chart? Are you a project, programme or portfolio manager? And what is the expected usage; as an active tool to schedule and manage activities, as a visualisation tool for updating or perhaps both?
Considering the role of the creator of a Gantt Chart is essential to the level of detail, as project management calls for a deeper level of detail of activities than for example portfolio management. The level of detail may also be impacted by additional recipients or users, as a steering committee does not necessarily need a detailed task-based chart, but rather an overview, illustrating how a project is progressing.
Therefore, the recipients and purpose perspective determine the usage of the Gantt Chart, hence assisting you as applicant in deciding on the scale of the tool. In order to apply the Gantt Chart, the application section introduces questions and reflections on how to address the recipients and purpose perspective in practice. Furthermore, the reflections will suggest what to implement, with regards to the purpose of the Gantt Chart.
When answering and reflecting on the questions, you will get an idea of the overall setting of you Gantt Chart. Are you for example using the chart as a personal tool to manage a personal situation, the chart could simply be created using a spreadsheet or drawn on a piece of paper. In a professional setting a simple version can also be useful, however you should consider other users and recipients. If multiple users are going to work with the chart either over time or for example in a workshop, the chart should be available in a spreadsheet placed on a platform accessible for all users or a Gantt Chart Software. Furthermore, a group accessed chart could also be represented on a physical board or flip chart, depending on whether the group has physical space available for such means. If the tool is used as a visualization tool for external partners, such as a steering committee or management group, appearance and comprehension should be considered, as the chart should be easy understandable. With regards to presentation, it should also be considered, whether the chart represents a snapshot or whether it should be dynamic, in order to allow active adjustment.
As described in the overall concept of the Gantt Chart, the core element is the horizontal bars, representing activities. When using flip charts one can also use post its MÅSKE DEL OP I ONLINE, PRÆSENTATION og WORKSHOP
Example of a Gantt Chart in a spreadsheet
Example of a Gantt Chart on a board
DTU Example
Considering an example of a project represented by the development and completion of a study and its deliverables for a university course. The user can be a given group of students, working on a project as a team with group deliverables. The group might use a Gantt Chart to estimate when to delegate and solve different tasks in order to deliver the expected and required deliverables on time, hence leading to a chart that represents activities on high detail level. Furthermore, the group might also want a less detailed version, where the course responsible, teaching assistants or contingent stakeholders can follow the progress of the group project.
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
