This seems a fairly straightforward and easy question. However, we will show that there are multiple ways of looking at this and that an answer may not always be so straightforward.
 
Is a project successful when it:
  • is on time?
  • is on budget?
  • delivered a quality product?
  • satisfies the users of the project deliverable(s)?
  • ...?
 
The answer is, it depends!
 
It depends on the success criteria that were (or were not) established at the beginning of the project.
If the only criterion their was was to build a machine that goes "bleeb" when you turn it on and it just does that when you turn it on, success!
If the criteria were to build said machine within a year and it still had to go "bleeb" when you turn it on and you did that, success.
If you were late a day, partial success.
 
It depends on the business/organizational objective(s) the project is to achieve.
If the objective of the project is for instance, to reduce wait times and thus increasing customer satisfaction within three months after the project, by replacing the call centre system at a call centre operator, then the project is a success if the customer satisfaction indeed goes up.
If the above project had the additional success criterion that the project is not to cost more than a X the project is a success if it did not cost more than X. If it did  cost more than X but still was able to satisfy the project objective than the project was a partial success.
 
When there is more than one criterion and when some of those criteria are related to the project objectives, as there should be, then you can see the question of project success becomes rather complicated.
 
For instance, in the above example of the call centre it is assumed (by the project owner) that there is a direct correlation and even causation between wait times and customer satisfaction. That seems an okay assertion. On the other hand, what if the new call centre system did indeed decrease wait times but also added one of those automated messages where you have to go through a slew of options before reaching (if ever) a real person and as a result decreased customer satisfaction?
 
What if there are no success criteria established at the start or during the project?
It is difficult if not impossible to measure something if you do not know what it is your are supposed to be measured against.
In other words, it is very important to clearly define what constitutes success but also to be very clear and specific on cause and effect including any assumptions you make with respect to causation and correlation.
 
As you can see there are many ways of looking at project (mangement) success.
Key point to note is that the sooner you, as the project manager or the project owner, establish the specific criteria for the project you are responsible for the better.
 
Having established the success criteria is of course no guarantee for success, it is merely an important first step!
 
See also:

PMO - What is it?

Sooner or later as someone interested in project management you will encouter the term PMO. This article will try to explain what a PMO is and what its benefits are.
 
Most commonly PMO refers to a Project Management Office. However it can also be Program of Portfolio Management Office.
 
There are dozens of defintions for a PMO. Just Google "Define: "Project Management Office:"
 
In short:
 
 
a PMO is an office of sorts (staff or line function) dealing with project management (related things).
 
 
This may seem simple but looking at all the variations out there it is the best we can come up with.
 
A more practical approach is to look at what type of functions PMOs perform in and for organizations:
 
  • Monitoring and Controlling Project Performance
    • Report project status to upper management
    • Monitoring and control of project performance
    • Implement and operate a project information system
    • Develop and maintain a project scoreboard
  • Development of Project Management Competencies and Methodologies
    • Develop and implement a standard methodology
    • Promote project management within the organization
    • Develop competency of personnel, including training
    • Provide mentoring for project managers
    • Provide a set of tools without an effort to standardize.
    • Standards and metrics Project knowledge management
  • Multi-Project Management
    • Coordinate between projects
    • Identify, select, and prioritize new projects
    • Manage one or more portfolios
    • Manage one or more programs
    • Allocate resources between projects
  • Strategic Management
    • Provide advice to upper management
    • Participate in strategic planning
    • Benefits management
    • Network and provide environmental scanning
  • Organizational Learning
    • Monitor and control the performance of the PMO
    • Manage archives of project documentation
    • Conduct post-project reviews
    • Conduct project audits
    • Implement and manage a database of lessons learned
    • Implement and manage a risk database
  • Execute Specialized Tasks for Project Managers
    • Scheduling
    • Contract management
    • Risk Management
    • Budget Management
  • Manage Customer Interfaces
  • Recruit, Select, Evaluate, and Determine Salaries for Project Manager
As with most organizational functions, not all fucntions will be perfomed by all PMOs.
 
A second way of looking at what a PMO is is to consider the level of change:
 
  • Project Management Office
    • Focus: Successful delivery of projects: On time, on budget, to scope.
    • Orientation: Execution
    • Potential Cultural Challenge/Disruption: Low
  • Program Management Office
    • Focus: Successful delivery of both projects and programs (programs: multiple projects and line activities coordinated for a single outcome).
    • Orientation: Strategy and Execution
    • Potential Cultural Challenge/Disruption: Medium to High
  • Portfolio Management Office
    • Focus: Construction of a portfolio and delivery of business results designed to achieve the business goals of the organization as well as quality execution of projects and programs.
    • Orientation: Business Results and Execution
    • Potential Cultural Challenge/Disruption: High
  • Planning and Portfolio Management Office
    • Focus: Bidirectional interaction with the management team in the creation of plans, development of the portfolio, and delivery of business results as well as quality execution of projects and programs
Please note that the above depends on the definition of project, program and portfolio. Again, there is no universal agreed defnition of these terms. This is a serious problem by the way!
 
All things considered a well implemented and organized PMO can have the following benefits:
 
  • Predictable and repeatable use of project management tools and techniques.
  • Growing staff professionalism in project management.
  • Standardization and portability of tools and techniques.
  • Facilitation of use of project management in becoming a core competency.
  • Improvements in organizational design and performance.
  • More productive and skillful project teams.
  • Profitability improvements.
  • External recognition for overall organizational performance.
 
Sources:
Arttoa, K., Kulvika I., Poskelab J, Turkulainena V., 2011. The integrative role of the project management office in the front
end of innovation. International Journal of Project Management 29 (2011), 408-421.
Aubry, M., Blomquist T., Hobbs, B., Müller R., 2010.  Project management offices in transition. International Journal of Project Management 28 (2010), 766-778. (One the three best-paper winners of IRNOP 2009!)
Aubry, M., Gemünden, H., Unger, B., 2011 The three roles of a project portfolio management office: Their impact on portfolio management execution and success, International Journal of Project Management 30 (2012) 608–620
Aubry, M., Hobbs, B., Thuillier, D., 2007. A new framework for understanding organisational project management through the PMO. International Journal of Project Management 25 (4), 328–336.
Aubry, M., Hobbs, B., Thuillier, D., 2008. Organisational project management: an historical approach to the study of PMOs. International Journal of Project Management 26 (1), 38–43.
Aubry, M., Hobbs, B., Thuillier, D., 2009. The contribution of the project management office to organisational performance. International Journal of Managing Projects in Business 2 (1), 141–148.
Kendall, G., Rollins, S., 2003. Advanced Project Portfolio Management and the PMO. J. Ross Publishing, Florida
Pemsel, P., Wiewiora, A., 2012, Project management office a knowledge broker in project-based organisations. International Journal of Project Management (12 pages)