10 Informatica Economică vol. 25, no. 4/2021 Estimating the Complexity of IT Projects Ion IVAN, Corneliu BĂRBULESCU, Gheorghe MATEI, Mihai Liviu DESPA Bucharest University of Economic Studies, Romania ivan@ase.ro, corneliu.barbulescu@ro.ibm.com, mgm1802@yahoo.com, despamihailiviu@gmail.com Project Management practice leverage concepts and models that try to maximize assessment accuracy with regards to effort and resource consumption. A central aspect is analysis of project complexity. The higher the complexity, the higher the cost and resource usage and risk. In this article, we define project complexity classes and propose models for estimating those. Key factors that drive complexity have the utmost importance. Ultimately, guidelines on translating project complexity into cost and duration estimation are established. Keywords: Complexity, Models, Project Management, IT Projects, Costs, Estimates DOI: 10.24818/issn14531305/25.4.2021.01 Defining the concept of complexity The objective of this article is to study the complexity of computer systems in order to build models that are used to increase the performance of measurement tools used during the implementation of projects. Similar to a set, complexity should be considered a primary notion, and its clarification should be done using examples. Everything that is subjected to analysis must be first taken as a whole, consisting of interdependent components. Its components are either different or of the same type. The links between the components are more numerous or less numerous. The intensity of interactions is either more intense or less intense. Everything that is the subject of analysis must be assessed by structure and number of components, diversity of components, and links between components. Projects in general and IT projects in particular are characterized by high complexity due to the following: high degree of unknown in terms of requirements for features that need to be implemented (requirements are most often incomplete), the diversity of activities involved in the implementation, the number of different types of raw materials used, the dynamics and intensity of the financial flows, high probability of risks occurring at all stages of development, the effects of decisions taken throughout the implementation cycle, reliance and dependency on subcontractors, and variations between what was planned and what was actually achieved. Once we are able to fully comprehend complexity and once we are able to define it as a quality characteristic of the entity that’s being analyzed, the next steps are: identify relevant factors that influence it, establish a set of exogenous variables, build models of complexity, and use of complexity in developing estimates. All completed, ongoing or future projects are classified according to complexity in simple projects, medium complexity projects, high complexity projects and very high complexity projects. If building a house is considered to be a simple project, building a four-story building is considered to be a medium complexity project, building a block of flats with related infrastructure is considered to be a project of high complexity, then the project aimed at the construction of an Olympic village with hotels, gyms, stadiums, swimming pools, athletics tracks and many other facilities, will be considered a project of very high complexity. The same is true for IT projects. There are simple projects that consist of source code of several thousand lines, implemented by a team of no more than five programmers. Very complex projects are those carried out by teams of at least 100 high-class professionals, in which the number of modules exceeds the order of thousands and for the implementation of which advanced technologies are used and quality management is mandatory. Computed complexity of the IT project is obtained by aggregating the data actually measured during the project life cycle. 1