Project planning and scheduling Literature Review

Project planning and scheduling Literature Review

Project planning and scheduling Literature Review
Project planning and scheduling Literature Review


Definitions and objectives of project planning  

The definition of project planning has been considered across broad front by both construction researchers and practitioners. For example, project planning is defined as a set of established processes used to make a decision on what tasks must be performed to achieve the project’s set objectives within schedule and cost. 
The authors further stated that planning involves the development of realistic schedules and cost estimates, the assignment and coordination of resources, as well as taking account of the views of project stakeholders. Project planning can also be regarded as an iterative process or procedure utilized to define project scope, develop and refine project objectives and set the course of actions to run a project according to specified standards of quality. 
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Baldwin and Bordoli state that regardless of the definition chosen for project planning, it has the objective of achieving a number of common factors including the production of realistic schedules and costs, the completion of a project to defined standards of quality, design criteria, project resources, health and safety, and meeting project stakeholders’ expectations.   More recently, it has been argued that planning and scheduling should be recognized as two separate, but closely related, activities that should not be performed concurrently in practice. 
According to Baldwin and Bordoli (2014, p.9): “[…] planning may be an iterative process but the tasks of planning and scheduling should not be attempted concurrently. Planning should precede scheduling. Scheduling should never precede planning. It is not a good practice to plan whilst scheduling. It is not a good practice to schedule whilst planning. Planning and scheduling therefore requires timing, organization and discipline. On larger projects, where planning and scheduling will be separate tasks undertaken by different people, it is easier to differentiate between the two tasks, and the tendency to confuse the roles of planning and scheduling is less likely to arise.”   
On the basis of the distinction between planning and scheduling as two separate tasks, Baldwin and Bordoli (2014) simplified the objective of planning and scheduling as follows: “the main objective of planning is to ensure that things happen successfully. This requires objectives to be established, tasks to be identified and progress to be monitored. The project schedule provides the basis for measuring progress, the basis for regular review and an updating of the plan” (Baldwin and Bordoli, 2014, p.13).  
From project management perspective, project planning and scheduling involve interrelated inputs and detailed deliverables that are to be implemented according to their assigned objectives. These objectives should be effectively defined and controlled early in planning and during execution for successful project performance. Figure 1 presents an overall view of planning and scheduling inputs and related functions (objectives) of each assigned input (or project activity). 
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Significance of project planning and scheduling  

The significance of project planning was recognized in early construction studies, in which it was argued that project planning needed to be improved by considering more efficient management strategies in planning. According to Dvir et al. (2003), there is a strong correlation between successful project planning and the success of a project from the perspective of project stakeholders. These authors also indicated that clear definitions of functional and technical specifications in project planning can lead to more effective execution of projects. They also found a strong correlation between successful implementation of planning procedures and benefits to project stakeholders. 
Such findings are confirmed in a later study which indicated that project success can be measured in view of the quality of project planning; whereas poor planning means uncontrolled alterations in the planning variables of time, cost and quality. Zwikael (2009) argued that many construction projects are more likely to be subject to the risk of poor project planning when compared to projects in non-construction sectors. Zwikael assessed the significance of project planning in construction projects and found that the extent of use of proper project planning by project managers and other project stakeholders was not at the optimal level of project requirements. He further argued that a strong emphasis should be placed on defining the project scope, project activities and costs (or budgets).   
Regarding project scheduling, the development of a good project schedule is vital to an understanding of project performance and control. Good scheduling represents a roadmap for project managers, planners and schedulers in monitoring and tracking critical activities and milestones during the progress of a project. Good project planning and scheduling can provide tangible benefits for key project stakeholders. 
Important benefits of good planning include:      
the ability to forecast resource requirements and costs;     
  • the ability to develop more realistic schedules with clear time deadlines
  • the ability to communicate with clear and reliable information to project stakeholders;     providing reliable information for risk and  opportunity assessment
  • providing good information for monitoring and control
  • minimizing materials wastage; and     
  • providing a strong basis for team coordination and assisting in the negotiation of contractual claims.   
  • These benefits cannot be achieved without strong commitment and knowledge on the part of project managers and other project stakeholders on how to manage planning and scheduling most effectively. 

Planning and scheduling methods and tools 

- Overview  Planning and scheduling methods and tools are regarded as essential parts of project planning and scheduling. It could be argued, therefore, that failures in project schedule performance should call for a specific focus on the effectiveness of existing methods and tools for managing construction schedules. In current practice, various project planning, monitoring and control methods and tools, in both traditional and modern approaches, are in use. 
Planning and scheduling methods vary in use, ranging from traditional approaches such as line-of-balance, the critical path method (CPM) and program evaluation and review technique (PERT) to more sophisticated methods such as critical chain project management and the Last Planner System. Based on these methods and tools, project scheduling can be classified into two main groups: resource-driven scheduling and time-driven scheduling. Resource-driven scheduling can be defined as a schedule that is driven by, and limited to, available resources (i.e. technical and human resources); examples are line-of-balance and the Last Planner System. Time-driven scheduling concerns the traditional scheduling of project activities based on estimated duration and their dependency relationships, regardless of resource limits; examples are CPM and PERT.  
These methods are already integrated into software to handle the complexities of large-scale construction project schedules. However, the complexity of project schedules can hamper the understanding of the application of these different methods and tools when executing and controlling the project. Consequently, the effectiveness of scheduling using different methods and tools should be properly assessed by project managers and their planners. Ahuja and Thiruvengadam (2004) indicated that the construction industry has struggled to become specialized in certain types of projects that require more sophisticated methods and tools to manage schedules than is possible using a traditional approach. 
The authors asserted that: “[…] the most utilized scheduling tools in the construction industry are CPM/PERT. However, the limitations of these tools are also being realized and research is going on to improve these tools and increase utilization of other tools such as linear scheduling techniques, simulation techniques, genetic algorithms for construction activities”.  Despite advances in many scheduling techniques, there are still many challenges in achieving a fit-for-purpose schedule, within the allocated time and available resources, using different methods and tools. 
These studies suggested there might be a need to determine more appropriate mechanisms for gaining a proper understanding of the underlying concepts of different methods and tools. Yang (2007) introduced a knowledge-based construction scheduling framework to enable a better understanding of the different scheduling problems and the different methods and tools used to handle them. Yang also identified areas that need to be covered in the knowledge domain of construction scheduling.  
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Communication and presentation of project schedules  

Project schedules can be presented and communicated in many ways, including simple activity lists, bar charts with dates, or network logic diagrams.  When projects become larger, it is difficult to present all tasks and information on one chart. Schedules can be divided into smaller entities, also called hierarchy of charts. Clough et al. (2000) argue also that schedules must be established on a hierarchical basis, and a schedule at a particular level of detail must be expanded to more detail when the execution of the work comes closer. 
Traceability between different schedule hierarchy levels is important to maintain consistency throughout the scheduling process. Winch and Kelsey (2005) have described that a high level planning has to incorporate many lower level plans and plans of subcontractors. Lower-level plans often confirm the robustness of the higher-level plans.  A milestone schedule is a strategic plan above all other schedules, which defines intermediate products to be achieved. It specifies the logical sequence of states the project must pass through, indicating what is to be achieved in each state, but not how it is to be achieved. The entire project scope is defined in this scheduling level. (Turner, 1999)  Below the milestone schedules is usually the master schedule, which outlines the main work packages and represents the major milestones. 
A master schedule is a type of project schedule which indicates the major project tasks without too much detail. Usually, it is used by the top and project management for reviewing and planning the entire project. It is prepared during the project development phase and after that it is periodically updated during project implementation. The project manager with the project team formulate the master schedule in a top-down fashion.  Next in the hierarchy are schedules at an intermediate level, where master-level tasks are presented in more detail, with sub-tasks. Usually, this level of schedule allows project and line managers to do resource planning.  At the bottom level, the schedule tasks are derived from tasks of intermediate-level schedules. These schedules are utilized by site personnel, supervisors, and technical specialists to plan and control activities on a daily or weekly basis. 
Task schedules are more detailed and contain activities at the work package level. Lower-level managers and supervisors can focus on detailed tasks of their own discipline without being interfered with by other areas they are not interacting with. Task schedules are prepared by line managers and including higher-level milestones and tasks from master schedule broken down into detailed ones. The master schedule is upgraded with necessary details gained from task schedules.  Winch and Kelsey (2005) has presented the hierarchy of construction project planning in Figure 1. The boxes in the figure represent contractually binding documents. The process starts from the client’s (owner’s) strategic programme and moves on according to arrows. The contractually-binding agreement between the client and contractor is the master programme. 
The contractor prepares the target construction programme, which guides the procurement programme and the work contractor’s (subcontractor) programme. Within the target programme, subcontractors are given time windows where they are expected to perform their works. Within works contractors’ programmes, subcontractors schedule task execution at the level of the WBS. Often, construction managers do not reveal the master programme to the subcontractors, but provide a target  construction programme, which is tighter than the master programme, to get a buffer if the subcontractor’s programme slips. No alt text provided for this image
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The appropriate level of task detail in schedules is never ended subject for a discussion. Too little detail hampers project control because necessary information is not readily available. Too much detail makes a schedule too large and consequently difficult to interpret and laborious to manage. That level of detail is suitable which a person using the schedule knows exactly what needs to be done without having to rely on other information.  
Another issue to consider is the appropriate cycle for updating the schedule. That depends on the type of schedule. The rate of change in the project affects to the choice of schedule and cycle time. As a simple rule, the period between updates needs to be long enough so that the project team has had time to act on the new information prior to the next updates.  Figure below presents a hierarchy, which contains five levels. In small-scale projects, only two levels can be used, while large and complex projects can have even more than five levels.
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Timing of Planning  

The timing dilemma of planning is another never ended subject to discuse. If the time interval between planning and implementation is long, the uncertainty concerning planned activity is higher. The higher the uncertainty in a project, the more difficult it is to plan. The earlier the project planner is involved with all relevant functional areas, the greater influence he has on its execution.  Analogy between planning horizon, degree of detail, and management level presented below.
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Laufer and Tucker (1988) have proposed solutions for the above-mentioned timing problems. They have connected the planning horizon, degree of detail, and management level in the Figure 3. The degree of detail should vary in the planning horizon, hence more detailed closer to implementation. Top managers maintain long-term horizon in planning while low-level management is interested in the coming few months. The degree of detail matches the management level as well as the hierarchy of schedules. Detail level varies across the given planning horizon from more to less detailed. 
For lower levels, detailed short-term plans of the immediate future are prepared more often, while for top management long-term plans with a low level of detail are established less frequently.  Alsakini et al. (2004) and Laufer et al. (1992) have suggested a proactive schedule management system in their study. It allocates less detailed scheduling to the home office and more detailed planning and control to the site organizations. This model facilitates dialog between project stakeholders because subcontractors are taken into the scheduling process early. 
The introduced system consists of a master schedule which is for the entire project. Work schedules are extensions of the master schedule by using a rolling window or look-ahead method. These schedules are established by project and site managers for a time span of two months at one-month intervals (for a12-month project). The third and most detailed level is of a two-three weeks action plan. 
That schedule is prepared and updated every one or two weeks and includes tasks from a rolling window presented in detail and indicating what will be executed on site. Corrective actions can be taken into account at the end of each period, when scheduling in detail for the next period. The master schedule is kept as a reference point and not changed, while detailed schedules can be used to bring the project back to track if needed.

Factors affecting planning and scheduling

A number of studies examined factors associated with the performance of planning and scheduling in construction projects; however, the main focus has been on the factors affecting schedule performance as an indicator of project success. For example, Hwang et al. (2013) studied critical factors affecting scheduling performance on public construction projects in Singapore. Their study indicated that poor site management and lack of effective coordination among project stakeholders, as well as inadequate competence in the project management team, were ranked as the most significant factors having a negative impact on schedule performance. 
Voth (2009) assessed significant barriers to scheduling at the Aeronautical Systems Centre (ASC), where the findings revealed a lack of team training and acquisition of knowledge about scheduling, shortage of resources, lack of disciplined project management and schedule as the factors having the most impact on scheduling. In another study, on schedule performance in Indian construction projects, Iyer and Jha (2006) found that factors such as the commitment of project stakeholders, competence of owners and a diversity of perspectives from project stakeholders in planning were considered significant factors in the success of project schedule performance. In addition, adopting proactive scheduling, motivational programs and effective communication approaches are important factors for schedule performance (Nepal et al., 2006).  
Snoo et al. (2011) assessed the factors (or criteria) affecting the performance of scheduling from the perspectives of a number of project stakeholders. The authors revealed that project schedules did not seem to be properly considered by both project managers and their planners/schedulers, as many criteria were ignored while developing and executing the project schedule. These criteria concerned reliability and robustness of information in the schedule, resource utilization and constraints, skill and competence of the planners/schedulers, and the level of uncertainty and complexity within the internal and external environments. The authors developed a scheduling performance measurement framework which categorized the factors (or criteria) impacting schedule performance into four main groups as shown in Figure below.  
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Relatively few studies have investigated and analyzed factors affecting project planning processes. Yang and Wei (2010) assessed factors causing delay concerning the planning and design stages of construction projects. They found that changes in the requirements of project stakeholders, especially owners, poor scope definition and an unrealistic initial or baseline plan were the top factors causing delay to a project. 
Consequently, there is a need to focus on factors affecting project planning, which in turn have a negative impact on the performance of the project. Dvir et al. (2003) examined the relationship between project planning and project success from the perspectives of project stakeholders. They found that the effective definition of project scope at the early planning stages is significant to the success of a project. The authors further revealed that the inadequate involvement of project stakeholders will negatively affect the effectiveness of planning.   
Earlier research indicated that factors impacting project planning should be evaluated from two perspectives – factors affecting the formulation of plans within the organizational environment and factors affecting implementation of plans within the project environment (Faniran et al., 1998). According to these authors, examples of factors related to project environments are variables concerning planning time, inputs, cost, investment of resources, planning control and attitude of top management. 
Variables related to the organizational environment included decision-making processes, organizational structures, availability of resources, control and communication mechanisms, and specialization of firms in planning. A model proposed by these authors is portrayed in Figure below.

Impact of Schedule Quality on Project Success

Although the schedule is defined as a critical success factor of projects, the way it causes the effects is not usually described. Raymond and Bergeron (2008) have introduced DeLone and McLean’s information systems success model (ISSM) and Davis et al.’s technology acceptance model (TAM) and adapted these to understand the impacts of PMIS on project managers and on project performance. 
I have adapted the model of Raymond and Bergeron further to verify the impact of schedule quality on project management and project success. The model in Figure 4 is composed of five constructs, namely, the quality of a schedule, the quality of schedule information output, the use of a schedule, the impacts on project management, and project success. The factors are connected to each other with arrows, and connections are described as follows.

Connection 1: Better schedule quality is associated to better quality of information output (availability, relevance, reliability, precision and comprehensiveness).  
Connection 2: Better schedule quality is associated to greater use of schedules. Good schedule quality positively influences willingness of use.  
Connection 3: Better schedule quality is associated to greater impact on the project management. Higher schedule quality positively affects project management’s decision-making.  
Connection 4: Better quality of information output is associated with a greater impact on the project management. How the schedule information output is formatted and communicated impacts project management.  
Connection 5: Better quality of information is associated to greater use of schedules. If the quality of information output is high, it increases users’ trust of the information.  
Connection 6: Greater use of schedules is associated to greater impacts on the project management. Increased use of schedules has a positive impact on the project management in terms of better performance of users and in support of decision-making.  
Connection 7: Greater use of schedules is associated with a greater impact on project success.  Connection 8: Greater impacts of schedules on the project management are associated with greater impacts on project success. Projects led by more efficient managers, due to their use of high-quality schedules, tend to be more successful in terms of meeting schedules, budgets, and specifications.

Better quality of schedules and, thus, quality of information output increases the opportunity of schedules to be used, which in turn allows the process to have a positive impact on the project management. Quality of information output leverages the project manager’s work as a professional if the manager has access to schedule information of high quality and he or she uses schedules more intensively and more extensively for planning, controlling, monitoring, and reporting activities. A combination of quality information and extensive use of schedules allows a project manager to feel more effective and provides better support for decision-making. 

Project stakeholders’ roles and behaviors in planning and scheduling  Improving the effectiveness of project planning and scheduling also requires an understanding of the roles and behavior of stakeholders in a project organization. Little research has addressed such roles and behavior, although some attempts have been made to examine project stakeholders’ attitudes in construction projects. In this regard, Yang et al. (2009) revealed that the assessment of project stakeholders’ behavior and attributes is crucial for successful, i.e. predictable, execution and delivery of construction projects. 
More recently, Yang et al. (2014) found that successful decision-making processes in construction projects require understanding and management of attributes, behaviors and management strategies related to project stakeholders. In this connection, the authors studied the correlation, from the perspective of project stakeholders, between their attributes (power, urgency and proximity) and their behavior (cooperative potentials, competitive threats and opposite and neutral positions). Their study revealed that there is need to try to understand such attributes and behaviors in construction projects. 
Prior to this study, Walker (2011) suggested that organizational behavior and interactions among various project stakeholders do not appear to be properly considered in practice and expressed this concern as follows: “[…] there is great scope for the behavioral characteristics of those involved to become significant in the success of firms and a project as a successful construction project required high levels of collaboration and communication. Inappropriate behaviors can have a serious effect on the smooth running of projects” (Walker, 2011, p.7).  It is important, therefore, to understand roles and behaviors of project stakeholders, as they can serve as critical factors for successful project performance. Understanding the behavior of project management leadership in terms of competence, technical experiences and decision-making attitude is crucial to the success of a project. 
Additionally, an empirical study of the understanding of such management roles affecting project performance indicated that the definition of roles and responsibilities was considered as the factor that should be given priority when managing a given project (Anantatmula, 2010).   With a specific focus on organizational behaviors, French (2011) defined organizational behavior as the attitude of project individuals or groups and their impact on the organization at both the management and project levels. In the context of project planning and control, a study by Walker and Shen (2002) found that effective project planning and control is directly influenced by the organizational culture as well as the norms and values of both the project team and individuals. 
An empirical study by Johansen and Wilson (2006) indicated that the roles of particular project stakeholders (i.e. owners, contractors, office based planners and site-based planners) in the development and control of construction planning should be clearly defined and coordinated for a successful project. From a broader perspective of project management, roles and responsibilities of the project management team should be outlined. However, management roles and the behaviour of project stakeholders at particular stages, such as planning and scheduling, need further assessment.       
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                                              Dariusz Wolejszo
Project Control specialist offering more than 15 years of leadership in design, construction, project development, and commissioning of high-profile oil, gas, petrochemical and power facilities.  Strong experience in a project controls management role, working for international construction companies.  
Great understanding of Planning, Cost, Estimating, and document control. Excellent communication and interpersonal skills. Team player, self-driven and good in high pressure dynamic situations.  People and result orientated individual with strong understanding the motivational requirements whilst working in projected organizations.  
Oil & Gas (Onshore & Offshore), Power Plants, Shipyards, Railway – ERTMS

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