Since then, and encouraged by the example of earlier adopters, thousands of projects around the world are using Agile methodologies, from start-ups with just 3 workers to large transnational companies and in almost most of businesses sectors.We will review in this work some of the most popular Classic project management methodologies and later focus in Agile methodologies. We will show pros and cons of both types and indicate cases where one approach is more suitable than the other. We will end showing a practical use case of Scrum methodology in Spotify and one hypothetical case were Scrum is used.52. Classic project managementProject management methodologies, developed in the last decades of 20th century, are called Classic methodologies, and are based on the planning, monitoring and controlling of the execution through systematics and repeatable processes.• It establishes as success criteria obtaining the defined product in the foreseen time and with the estimated cost.• It assumes the project is developed in a stable and predictable environment.• Its objective is to complete the project or the phases at schedule, and to maintain the budget and the resources.• Divides the processes in five phases: initiating, planning, executing, monitoring and controlling, and closing. This is called the project’s “life cycle”.Fig. 1: Scheme of the phases of the classic project management methodology.First, we will discuss some Classic project management methodologies:2.1 WaterfallThe Waterfall Method is the simplest way to plan a project. Tasks flow down the list in sequential order, just like a waterfall. One step must be completed before starting the next, phases never overlap. Requirements are defined in full at the beginning, at the top of the waterfall, before any work starts. The outcome of one phase is the input of the next one. In a pure Waterfall implementation going back to a previous phase is not possible, the only6possible flow is downwards. Typically, there’s a review of requirements at the end of each step.This system is very straightforward and easy to implement for managers. For workers it’s easy to understand how the project is structured. It is also very simple to use.Usually each phase is carried out by a different department or group of people that are specialised and have the required skills for the phase.Fig. 2: Scheme of the waterfall phases.The sequential phases in Waterfall model are:• Analysis and requirements gathering: all possible requirements are gathered, and an analysis of the project is made.• Design: all the requirements gathered in the previous phase are studied and the project is designed.• Implementation: the system is developed in small units and each unit is tested.• Integration and testing: all the units are integrated and the whole system is tested.• Deployment of system: once the functional and non-functional testing is completed, the product is deployed in the customer environment or released into the market.• Maintenance: the issues are fixed, and some new versions and patches are released. These changes are delivered to the customer environment.72.2 PMI’s PMBOKThe Project Management Institute (PMI) is an association which mission is to promote the development of knowledge and skills required in project management. PMI provides services like development of standards, research, education, training seminars and providing accreditation in project management.The PMI’s most famous product is the Project Management Body of Knowledge (PMBOK). PMBOK is a collection of processes, best practices, terminologies and guidelines. It is not a methodology but a guide of standards that every project manager can adapt to each project.PMBOK recognises five process groups and ten knowledge areas typical of almost all projects. These process groups are simply phases that each project goes through.The five basic process groups are:1. Initiating2. Planning3. Executing4. Monitoring and controlling5. ClosingThe ten knowledge areas are:1. Projects Integration Management. Processes necessary to define, consolidate, and coordinate all the other processes and project management activities.2. Project Cost Management. Processes involved in the projects finances. The main activity in this knowledge area is preparing the budget.3. Project Scope Management. Processes to ensure that the project includes all the work required, and only the work required, to complete a project successfully.Initiating InitiatingInitiating Initiating InitiatingInitiatingPlanning PlanningPlanningPlanningPlanningMonitorinMonitorinMonitorin MonitorinMonitorinMonitorinMonitorinMonitoring and g and g and g and controllingcontrollingcontrolling controllingcontrollingcontrollingcontrollingcontrollingcontrollingExecutingExecuting ExecutingExecuting ExecutingExecutingClosing ClosingClosingClosingClosingClosing84. Project Communication Management. Processes that spread information and ensure information is exchanged continuously and, more important, understood by all members concerned.5. Project Time Management. Processes needed to ensure the project is completed before the specified deadline.6. Project Human Resources Management. Processes that organize, manage and lead the project team.7. Project Quality Management. Processes that define the success of a project. Quality is managed at every stage of the project.8. Project Procurement Management.9. Project Risk Management. Processes involved in preparing for and managing unexpected events.10. Project Stakeholder Management. Processes required to identify stakeholders, understand their expectation and impact on the project and ensure that this is delivered.2.3 PRINCE2PRINCE2 is a waterfall project management methodology that includes principles, themes and processes. ‘PRINCE’ stands for PRoject IN Controlled Environments. It was created by the UK government in 1996, originally for IT projects.PRINCE2 emphasises dividing projects into multiple, manageable stages. This separation allows an efficient resource management and, a control andThe PMBOK method is documented within the book A Guide to the Project Management Body of Knowledge. This guide must be constantly revised and updated. The current edition is the sixth, published in 2017. It includes information about how to implement its approaches in agile environments.Fig. 3: A Guide to the Project Management Body of Knowledge.9monitoring very close to the actual work, which makes the development of the project controlled and organised.Fig. 4: PRINCE2 scheme.The PRINCE2 method is based on four integrated elements: principles, themes, processes and the project environment.The PRINCE2 principles are:1. Continued business justification. A project must make a good business sense, there must be a justifiable reason to be running and managing the project.2. Learn from experience. PRINCE2 project teams should continually take lessons from previous work into account.3. Defined roles and responsibilities. PRINCE2 project team should have a clear organizational structure and involve the right people in the right tasks.4. Manage by steps. Projects should be planned, monitored and controlled in a stage-by-stage basis.5. Manage by exception. People working within the project should be given the right amount of authority to effectively work within the environment.6. Focus on products. PRINCE2 projects focus on the product definition, delivery and quality requirements.7. Tailor to the environment. The project should be adapted to the project’s environment, size, complexity, importance, capability and risk.The PRINCE2 themes provide insight into how the project should be managed and describe the aspects that must be addressed in parallel throughout the project.101. Business case. Provides knowledge about whether a project is worthwhile and achievable. Is related to the business justification principle.2. Organisation. Defines the individual roles and responsibilities of the whole project team.3. Quality. Defining what quality requirements and measurements are and how are going to be achieved.4. Plans. Describes how targets will be achieved, the steps needed to develop the plans.5. Risk. Identifies, assesses and controls risks, uncertain events, and opportunities during a project.6. Change. How to handle changes that come up during the project.7. Progress. About tracking the project, based on the ongoing viability and performance of the plans and on how the project should proceed.The PRINCE2 also separates the running of a project into processes or stages, from the initial idea to the closer of the project.The PRINCE2 processes are:1. Starting up a project.2. Directing a project.3. Initiating a project.4. Controlling a stage.5. Managing product delivery.6. Managing stage boundaries.7. Closing a project.Fig. 5: PRINCE2 processes scheme.The key points of the classic project management are the work developed in phases, the division of work into teams of specialists, the development based in processes, and the estimation of the needed work followed by the execution to meet that estimation.