Gantt Chart, also known as Bar chart, was developed by scientific management master Henry Laurence Gantt (1861-1919) in 1917. It is a chart system method, and later His name is named. Often used for planning and sorting, the chart is one of the early attempts to link activities to time. On the eve of World War II, Gantt Chart became an important tool for planning and controlling military engineering and construction projects. It is still a common method of project management today and is regarded by social historians as one of the most important social inventions of the 20th century.

The inner thought of the Gantt Chart is relatively simple, it is essentially a line diagram. Among them, the horizontal axis represents time, the vertical axis represents activity (item), and the lines are used to show the planned and actual activity completion status throughout the entire period. Through the Gantt Chart, one can intuitively understand the time of the task plan and the comparison between actual progress and planning requirements.

The Gantt chart contains the following three meanings:

Displays activities in graphic or table form.

It is a general way to display progress.

When constructing a Gantt chart, the actual calendar and duration should be included, and weekends and holidays should not be counted normally during progress calculations.

Gantt chart consists of two-dimensional coordinates. In the Gantt chart, the horizontal axis direction represents time, and the vertical axis direction parallels information such as machine equipment name, operator and number. The chart uses lines, numbers, text codes, etc. to represent the planned (actual) time, planned (actual) output, planned (actual) start or completion time, etc. (as shown in Figure 1). By observing the planned activity lines and actual activity lines, you can clearly understand the progress of the actual activity.

There are two ways to represent the Gantt chart (as shown in Figure 2):

One is to be represented by rectangular bars;

The other is represented by triangle lines. Among them, the "△" in the task represents the planned milestone event and the actual milestone event. Different graphic identifiers can display the project progress related information more clearly. [Figure 2: Two ways to represent Gantt charts] show two ways to represent tasks and progress with rectangular bars and triangle lines, including planned tasks, actual tasks, and presentation of milestone events on the timeline. .

Drawing a Gantt chart generally follows the following steps:

Clarify the various activities and project contents involved in the project, including the project name (including order), start time, duration, task type (dependence/decision) and which task to rely on.

Create a Gantt chart sketch and mark all projects on the Gantt chart according to the start time and duration.

Determine the project activity dependency and timing progress. Use sketches to contact and arrange the project according to the type of project. This step ensures that when planning adjustments, all activities can still be carried out in the correct sequence, that is, all dependent activities can only be carried out as planned after the decisive activities are completed, while avoiding the critical path being too long (critical paths are penetrated by The key task determination of the project is always a key task, which represents the longest time-consuming project, and also represents the shortest possible time to complete the project, and will change due to changes in the progress of individual activities). In addition, project resources should be arranged reasonably to avoid abuse, and appropriate wealth time should be reserved for unpredictable events on the schedule (but wealth time is not suitable for critical tasks).

Calculate the working hours of a single active task.

Determine the executors of the activity tasks and adjust the working hours as needed according to actual conditions.

Calculate the entire project time, and professional software can automatically complete the calculation work.

When using Gantt charts, you need to pay attention to the following points:

The implementation lines in the Gantt chart should be drawn while making and being carried out simultaneously with the project implementation.

It is necessary to clearly distinguish between the planning line and the implementation line.

The implementation progress must be consistent with the actual situation.

When there is a difference between the planning line and the implementation line, please note the reasons for the difference.

In the quality control circle activity steps, the implementation lines of the two steps of analysis, countermeasure formulation, effect confirmation and standardization cannot be paralleled at the same time.

If the progress control is backward, the reasons should be investigated in a timely manner and corresponding countermeasures should be taken.

Gantt charts are mainly used for project planning and schedule control. With the help of Gantt Chart, managers can easily know the remaining work content of a task (project) and evaluate whether the work progress is ahead of schedule, lag or normal. It is an ideal project control tool.

In addition, Gantt Chart is based on the purpose of job sorting and can help managers describe the use of resources such as work centers and overwork hours. When used for load analysis, it can show the operation and idle status of multiple departments, machines or equipment, so that managers can understand the workload status and make appropriate adjustments. At the same time, the Gantt chart can also be used to check the progress of work completion and clarify which work is completed as scheduled and which are completed ahead of schedule or postponed.

The Gantt Chart is characterized by combining the two functions of planning and schedule. Although it does not directly represent the correlation between tasks with graphs, it emphasizes the correlation of time information, especially for progress tracking after the project starts. By using different colors to identify project progress, such as completed parts, unfinished parts, early completion or delayed completion parts, remaining time, etc., the progress of the project can be more intuitively displayed.

Graphical summary, as a general technology, is easy to understand.

It is suitable for small and medium-sized projects. It is effective when the general project activities do not exceed 30.

With professional software support, users do not need to worry about complex computing and analysis work.

Its main advantage is that it can compare the planned progress with the actual progress in the same picture, which can intuitively present the actual progress of the project, which is conducive to progress control.

The Gantt chart only partially reflects the triple constraints (time, cost and scope) of project management, and mainly focuses on process management (time), and lacks the implementation of costs and scope.

There are certain shortcomings in the software. Although project management software can depict the inherent relationships of project activities, when there are too many relationships, complex line charts will increase the difficulty of reading Gantt charts.

To avoid distracting readers, it is best to avoid using grids.

[Figure 3: Quality Improvement Plan Gantt Chart] shows the distribution of the expected months required for each work project in the quality improvement plan on the timeline in the timeline, covering determining the scope of improvement, defining the plan, managing review, and providing Training, data analysis and other work items.

From the Gantt Chart example (for quality improvement planning) in Figure 3, it can be seen that work items 3 and work items 4 are more critical to the entire work plan and cannot be delayed, otherwise it will affect the overall progress. Work item 5 (data analysis) is also very important. If it cannot be completed, the quality improvement process will be hindered.

6.1.1. Conceptual meaning

6.1.2. Application Cases