Gantt charts:
Gantt chart, a type bar chart that illustrates a project plan, is named after Henry Gantt, its inventor.
Gantt charts are a project management tool that helps in planning and scheduling projects of any size, but they can also be useful for simplifying more complex projects.
This chart lists the tasks that must be completed on the vertical axis, and the time intervals that must be followed on the horizontal. The graph’s horizontal bars show the duration of each activity.
This chart helps you plan the activities and tasks required to complete a project.
These charts show when an activity should start and when it should stop according to a timeline.
Gantt charts can also be used to show the resources allocated to each task and what percentage.
Gantt charts can also help you track milestones and other significant accomplishments, such as the completion of a project phase or a key deliverable.
The Gantt chart shows the progress of the entire project. It can be used to determine if the project is ahead, behind, or on time compared to the baseline plan.
Gantt charts are useful for monitoring progress and setting priorities.
Gantt charts have two major flaws: they don’t show the dependencies of tasks to one another and it doesn’t show which tasks are ‘critical to finishing the project on schedule.
Gantt Chart is a reliable method to estimate the scope and cost for a software development project
Here’s an example of a Gantt Chart:

Critical Path Methodology (CPM).

The critical path is a sequence of activities whose total activity time is longer that the sum for any other route through the network.
Critical Path Analysis is used in all types of projects, including software development, software development, research projects and product development. It can also be used for maintenance and plant construction.
This method of mathematical analysis can be applied to any project that has interdependent activities.
Every project schedule has at least one critical path. This is usually the case for non-manipulated schedules.
Because everything should go according to the schedule, the critical path will give the project the shortest completion time.
Activities that aren’t in the critical path can be slowed.
Slack time is the time that a task can be delayed, but not cause another task to be delayed or affect the completion date of an overall project.
Activities on a critical pathway have zero slack, and vice versa, activities with zero idle time are on a crucial path
If you plan to add staff to tasks that place time constraints on a project’s duration, it is important to validate the critical path first.
Here’s an example of the Critical path methodology.

The above image represents a project. Let’s call it Project A. The stages of the project run from Stage 1 through Stage 11. There are many ways to complete the project. The numbers above the arrows represent the time it took to complete each task. Let’s now calculate the time it takes to complete each task. In this case, path 1 is the longest, and takes the longest time to complete the project.
Comparison of Gantt chart versus Critical Path methodology
Gantt charts don’t show how activities relate to each other, but Critical Path methodology does.