II – Planning

• Why plan
• Project planning tools: Gantt Chart and PERT Network

Planning in project management refers to all activities related to organizing, scheduling, monitoring, coordinating, and managing the project to meet stakeholders’ requirements.
The project manager plays a key role in this process, ensuring that objectives are achieved on time, with the available resources, and according to the expected quality.

 

II.1 Why plan?

Projects often fail due to a lack of rigorous planning. Several reasons explain the importance of this step:

• Projects frequently exceed deadlines, budgets, or fail to meet quality expectations.
• They operate in a complex environment influenced by:
• Internal factors (studies, marketing, production)
• External factors (market, politics, competition)
• Rigorous planning allows:
• Controlling deadlines and resources
• Organizing task sequences
• Anticipating risks and monitoring progress

II.2 Planning tools

The success of a project largely depends on rigorous planning to control deadlines, resources, and task sequences. For this purpose, several tools have been developed to help project managers efficiently organize and track project phases. Among the most used are the PERT Network (Program Evaluation and Review Technique) and the Gantt Chart.

These two methods are essential planning and project management tools:

• The PERT network allows analyzing task logic and identifying the critical path.
• The Gantt chart provides a graphical representation of these activities over time.

Together, they facilitate forecasting, controlling, and monitoring project progress.

II.2.1 The Gantt Chart

The Gantt Chart is a widely used representation tool today that models the scheduling of tasks required to complete a project. It was invented in 1917 by Henry L. Gantt. This method is intuitive and simple; everyone can read it, making it an excellent communication tool among project stakeholders.

The Gantt method is usually associated with a PERT network, but for clarity in this course, it will be explained starting from an activity inventory.

The Gantt method is based on representing a project graphically over time using a horizontal bar chart:

• The position of the bar indicates the start and end dates of a task.
• The length of the bar reflects the task duration.
• Bars can overlap to show tasks carried out in parallel.
• Links or arrows can be added to illustrate dependencies between activities.

Advantages of the method:

• Simple and accessible reading
• Easy tracking during the project by comparing planned and actual dates
• Start and end dates of each task are read directly on the time scale
• Resource assignment allows establishing a workload plan
• Provides a detailed description of costs

Disadvantages of the method:

• Not suitable for planning too many tasks
• Critical tasks are not highlighted
• Does not show links between tasks

Example: Cleaning and restoring a coral reef

Project objective:
Conduct an ecological operation to clean the seabed and restore a coral reef damaged by pollution and human activities.
Estimated total duration: 10 weeks

Step	Task	Estimated Duration	Depends on
1	Environmental study and permits	2 weeks	—
2	Recruitment and training of divers	2 weeks	1
3	Underwater inspection and reef mapping	1 week	2
4	Marine debris cleaning operation	3 weeks	3
5	Replanting coral fragments	2 weeks	4
6	Ecological monitoring and final report	2 weeks	5

Simplified Gantt chart (in weeks)
Each █ = 1 week

 

Weeks (top)	0–1	1–2	2–3	3–4	4–5	5–6	6–7	7–8	8–9	9–10	10–11	11–12
Environmental study and permits	█	█
Recruitment and training of divers			█	█
Underwater inspection and reef mapping					█
Marine debris cleaning operation						█	█	█
Replanting coral fragments									█	█
Ecological monitoring and final report											█	█

X-axis: Weeks
Y-axis: Tasks

Reading the chart:

• The project begins with site study and legal authorizations.
• Divers are trained before reef inspection.
• Cleaning operations take several weeks, followed by coral replanting.
• Finally, an ecological monitoring phase evaluates results and produces a final report.

Key points:

• The Gantt chart helps visualize the marine restoration schedule
• It highlights dependencies between steps
• Facilitates management of human and material resources (divers, equipment, boats, etc.)

II.2.2 The PERT Method (Program Evaluation and Review Technique)

PERT is a scheduling method designed for complex and long-term projects. It relies on analyzing task dependencies and allows identifying the project’s critical path.

Terminology:

1. Event (or milestone)
   An event (also called a node or milestone) represents a key point in the project.
   It is the start or end of one or more tasks:

• It consumes neither time nor resources
• It simply marks the completion of one or more activities
• Often represented by a numbered circle (or rectangle)

Example:
○1 ————(A, 5 days)————> ○2

• Event 1 is the start of task A,
• Event 2 is its end

2. Task (or activity)
   A task represents work to be done between two events: a start and an end.

• Consumes time and resources
• Represented by an arrow connecting two events
• Each task has an estimated duration

Example:
○1 ────(Task A, 4 days)────> ○2

• Task A starts at event 1 and ends at event 2 after 4 days

3. PERT Network
   The PERT network is the organized set of events and logically connected tasks. It allows:

• Identifying task execution order
• Determining the critical path (tasks determining project duration)
• Calculating earliest and latest dates for each event
• Optimizing planning and avoiding delays

Simple example:

Network reading:

• ○1 → ○2: Task A (3 days)
• ○2 → ○3: Task B (5 days)
• ○2 → ○4: Task C (4 days)
• ○3 & ○4 → ○5: Task D (2 days)
• Task D starts after B and C, as required

Rules for representing a network:

1. Each network has one Start and one End event.
2. Each task has at least one start and one end event.
3. A task cannot start until its preceding tasks are finished.
4. Two different tasks cannot have the same start and end events simultaneously.
5. Tasks executed simultaneously have the same start but different end events (e.g., parallel circuit).
6. Tasks executed simultaneously and ending at the same event are called convergent.
7. Sometimes a dummy task is used to represent chronological dependency.
• Represented by a dashed arrow
• Has no name and zero duration

Advantages of the method:

1. Logical analysis of the project
2. Critical path identification
3. Better time management using optimistic, pessimistic, and probable durations
4. Decision-making support
5. Monitoring and control tool

Disadvantages:

1. Complex implementation
2. High preparation time
3. Often uncertain data
4. Difficult to update
5. Less visual than Gantt

Example: Coral reef restoration project

Objective:
Restore a degraded coral reef by optimally scheduling activities while respecting time and resource constraints.

Tasks:

Task	Description	Estimated Duration
A	Environmental study and permits	3 weeks
B	Diver training	2 weeks
C	Reef inspection	2 weeks
D	Reef cleaning	3 weeks
E	Coral replanting	4 weeks
F	Ecological monitoring and final report	2 weeks

Dependencies:

• A must finish before B and C
• B must finish before D
• C must finish before D
• D must finish before E
• E must finish before F

Simplified PERT network:

PERT simplifié

Reading the network:

• Project starts at event 1
• Task A must finish before starting B and C
• Task D starts after B and C
• Task E follows D, and F completes the project
• Critical path: A → C → D → E → F

Conclusion:

• Planning is essential for project success
• Gantt chart provides clear and simple visualization
• PERT analyzes dependencies and manages duration/resource constraints
• Together, they facilitate project management, monitoring, and optimization

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Exercises: Gantt Chart and PERT Network

Exercise 1: Organizing a training session

Task	Description	Depends on	Estimated Duration
A	Prepare program	—	2 days
B	Send invitations	A	1 day
C	Reserve room	A	2 days
D	Welcome participants	B, C	1 day

Question:

- Construct the Gantt chart by placing the tasks in the correct order according to their dependencies.

Solution:

Gantt Chart (in days):

Task	Day 1	Day 2	Day 3	Day 4	Day 5
A – Prepare program	█	█
B – Send invitations			█
C – Reserve room			█	█
D – Welcome participants					█

Interpretation:

• Task A starts day 1, duration 2 days
• B and C start after A, in parallel
• D starts after B and C, day 5
• Total project duration: 5 days

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Exercise 2: Bridge construction

Task	Depends on	Estimated Duration
Preliminary studies (A)	—	5 months
Material purchase (B)	A	3 months
Site preparation (C)	A	3 months
Foundations (D)	B & C	4 months
Structure assembly (E)	D	3months

Questions :

1.Construct the PERT network.

2. Draw the Gantt chart.

Solution:

1. Construct the PERT network

• Events:
• O1: project start
• O2: end of task A (start of B and C)
• O3: end of B
• O4: end of C
• O5: end of D
• O6: end of E (project end)
• Tasks on arrows:

Task	Start	End	Duration
A	O1	O2	5 months
B	O2	O3	3 months
C	O2	O4	3 months
D	O3 & O4	O5	4 months
E	O5	O6	3 months

 

 

 

 

 

 

PERT network diagram:

Explanation:

• Circles O1 → O6 are events
• Arrows A, B, C, D, E show tasks with durations
• D starts after B and C
• E starts after D

2.      Construct the Gantt chart

 

 

 

 

 

 

 

 

 

 

 

Gantt Chart – Bridge Construction Project

Task	M1	M2	M3	M4	M5	M6	M7	M8	M9	M10	M11	M12	M13	M14	M15	M16	M17	M18
A	█	█	█	█	█
B						█	█	█
C						█	█	█
D									█	█	█	█
E													█	█	█

 

 

 

Interpretation:

• The project starts with Preliminary studies (A) lasting 5 months.
• After A, both B (Material purchase) and C (Site preparation) run in parallel for 3 months.
• Then D (Foundation construction) starts after both B and C, lasting 4 months.
• Finally, E (Structure assembly) lasts 3 months and completes the project.