The effectiveness of resource levelling tools for Resource Constraint Project Scheduling Problem

doi:10.1016/j.ijproman.2008.08.006

International Journal of Project Management

Volume 27, Issue 5, July 2009, Pages 493-500

https://doi.org/10.1016/j.ijproman.2008.08.006 Get rights and content

Abstract

The PERT/CPM network techniques are based on the assumption that all needed resources will be available. The scarcity of resources is a usual reason for project delays. For the solution of the Resource Constrained Project Scheduling Problem (RCPSP) other methods have been applied. The objective of these methods consists in minimizing the project’s duration by considering both the precedence and resource constraints. Project Management software packages solve the resource conflicts using resource levelling. The paper evaluates the effectiveness of resource levelling tools of three popular packages by comparing the results when levelling two real construction projects as case studies.

Introduction

The CPM has been widely used for project scheduling, helping managers to guarantee the in time and on budget completion of the project. CPM provides useful information for the project, such as the critical path(s) and free and total float, which are essential for the efficient planning of a project. An advantage of CPM is the ability of managing by exceptions (critical and near critical activities) especially in large-scale projects [1]. However, CPM is based on the assumption that there are unlimited resources for the execution of the activities. Though in real projects, resources are not unlimited. Thus, scheduling without considering resource constraints gives unreliable schedules.

A survey conducted by Liberatore et al. [2] shows that 83% of professional project managers use project management software for planning and control, and that in construction industry resource levelling is used by 58% for planning and by 44% for project control. From the same survey it was derived that Primavera Project Planner and MS Project are the most popular software packages used for construction projects. By adding an open source package for comparing purposes, this paper examines the resource levelling capabilities of three PM software packages in two construction projects.

The paper is organized in five paragraphs. In the first, the theoretical background of the problem is formulated. Next paragraph presents the recent techniques, as they appear in the international literature, for finding more reliable schedules by considering resource constraints. After that, the objectives and the methodology of this paper are presented, and the paper closes with results and short conclusions.

Section snippets

Problem formulation

A project is represented by an Activity-On-Node network (AoN). It consists of n activities, where 1 and n are dummies and denote the start and the completion of the project. The fixed integer duration of activity j is indicated by d_j (1⩽j⩽n), its integer start by s_j (1⩽j⩽n) and its integer finish by f_j (1⩽j⩽n). There are K renewable resources with r_jk (1⩽j⩽n, 1⩽k⩽K), the constant resource requirement of activity j for resource type k, and α_k, the constant availability of resource k.

Literature review

However, a resource constrained project network may have a lot of equivalent schedules [1]. An example of equivalent schedules is given in Fig 2, where two equally good solutions of network A (Fig. 1) are depicted. Activities 3 and 4 have the same duration, resource requirement, predecessors and successors, but in schedule (a), Activity 3 is critical and Activity 4 has a significant float, while in schedule (b), Activity 4 is critical and Activity 3 has a significant float. Raz and Marshall [10]

Objectives and methodology

The objective of this paper is to analyze the quality of resource constrained scheduling of project management software, by evaluating two widely used software packages [2], Primavera P6.0 and Microsoft Project 2007, and one open source, Open Workbench 1.1.6. Furthermore, the paper compares the results with the previous versions of these software packages, e.g. Primavera Project Planner v.3.1, Microsoft Project 2003 and Open Workbench 1.1.3.

Project management software packages usually use

Results

On comparing the default options given from the software (Table 1), Primavera P6 gives the best results and is followed by MS Project in both the instances. Open Workbench has a great deviation especially in the second instance.

On comparing all the results (Table 2), Primavera P6 default and by LST rule give the best solution for both instances with an average deviation of 41.11%. MS Project is ranked 3 (46.14%) and is followed by P6 by RPWM and by LFT (47.19%). The worst result was given by

Conclusions

This paper evaluated the resource levelling capabilities of three project management software packages on two real construction problems. The results show that the project duration depends on the software or the method used. It could be supported that, for problems of that size and complexity and objective function the makes pan minimization, there is an increase in makespan from 41.11% to 167.79% of the resource unconstrained schedule and that Primavera P6 outperforms MS Project and Open

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View full text

The effectiveness of resource levelling tools for Resource Constraint Project Scheduling Problem

Abstract

Introduction

Section snippets

Problem formulation

Literature review

Objectives and methodology

Results

Conclusions

Comput Oper Res

Omega

Int J Project Manage

Int J Project Manage

Eur J Oper Res

Int J Project Manage

Int Trans Oper Res

Criticality in resource-constrained networks

J Oper Res Soc

Project management in construction: software use and research direction

J Constr Eng Manage

Heuristic algorithms for the resource-constrained project scheduling problem: classification and computational analysis

Some properties of schedules for large projects with limited resources

Oper Res

A heuristic model for scheduling large projects with limited resources

Manage Sci

Resource constrained scheduling within fixed project durations

J Oper Res Soc

Critical chain

Multiple schedules and measures of resource constrained float

J Oper Res Soc

Tools for resource-constrained project scheduling and control: forward and backward slack analysis

J Oper Res Soc