Projects
The simplest definition of a project is an objective that requires more than one action to complete (Allen, 2015, p.159). Project management professionals tend to broaden this concept to include multiple objectives over a period of time (Simplilearn, 2023). A CIO or program manager may take an even more proscriptive approach and select and evaluate projects based on the constraints of "time, cost, scope, quality, resources, and risks" (Eby, 2022).
Using the first definition, a successful project is one that completes the objective; and a failed project is one that does not complete the objective for any reason. In my experience smaller internal or independent projects that span a few weeks or months are often measured against this criteria. In the constraint-based approach a project may achieve the core objective and still be considered unsuccessful if it has taken longer, cost more, introduced risks, or grew beyond the original scope.
In my experience a small project with simple objectives is unsucessful only when the project is abandoned. A longer, larger or more complex project can be considered to have been successful or unsucessful based entirely on which metrics used to evaulate it. In this case completion of the objective is only one metric and may even involve deviation from the original objectives as the underlying or external factors evolve.
References
Allen, D. (2015). Getting Things Done: The Art of Stress-free Productivity. United Kingdom: Little, Brown Book Group Limited.
Eby, K. (2022). How to identify and manage constraints in project Management. Smartsheet. https://www.smartsheet.com/content/project-constraints
Simplilearn. (2023). What Is a Project in Project Management: Life cycle, and More. Simplilearn.com. https://www.simplilearn.com/what-is-a-project-article