Agile versus Waterfall Project Management: Decision Model for Selecting the Appropriate Approach to a Project

TLDR

Project management methods are broadly divided into plan‑driven waterfall and iterative agile approaches. The study seeks to compare the differences, benefits, and constraints of waterfall and agile methods and to develop a decision model for selecting the most suitable approach for a given project. The authors construct a decision model grounded in Adam’s 1996 framework, informed by a systematic literature review and 15 expert interviews, and based on 15 criteria across scope, time, costs, organizational context, and team characteristics. The model fills a research gap and, validated by expert interviews, provides practical decision support for choosing between waterfall and agile approaches.

Abstract

Procedural models for project management can be differentiated into plan-driven methods which follow a classical waterfall process and agile methods which follow an iterative, test-driven approach. This paper answers the following research questions: What are the differences, benefits, and constraints of these two approaches from a practitioner's point of view? How can a decision model be set up to select the most appropriate approach for a concrete project? This study develops a decision model for the selection of a procedural model for project management which is based on the modelling process described by Adam (1996). The research gap was identified based on a systematic and comprehensive analysis of the literature following Vom Brocke et al. (2009), which reflects the state-of-research. Insights gained were compared with empirical data from 15 expert interviews across different industries in Germany. The presented model systematically supports the selection of an appropriate procedural model for a concrete project based on 15 criteria subsumed under the following categories: scope, time, costs, organization context, and project-team characteristics. It closes a relevant research gap, both from a scientific perspective and from the practitioners' view. Expert interviews ensure practical relevance and significantly expand the state-of-research with regards to decision support on the project-management approach.