This is a far from straightforward issue in this organizational climate, as success is different for different stakeholders.
Historically, Project Success was based around delivering on time, within budget, and meeting the scope or quality parameters laid down at the start of the project. This is the so called 'triple constraints' model referred to by Arman above.
However, these days project outcomes/deliverables are more focused on 'value', and value is different for different groups of stakeholders, and at different points within the project. also, the 'triple constraints' are not as stable as they were, because projects are now operating within more turbulent organizational environments, where change is constant.
Historically, the literature on project success was based around the work of Morris and Hough, and Jeff Pinto and Dennis Slevin. This stuff was published in the late 1980s, and things have moved on from there. However, in today's project domain, project success is bound up with stakeholder issues and managing stakeholder satisfaction and expectations.
I agree with the answers you've gotten. I think you would need project success to be measured by the organization in which the project is occurring. The easiest variable to access would be some kind of ratings of performance.
I would see if you can send the project managers' managers a survey about their job performance. I would design that survey using 5-12 requirements from a job analysis (or from O*NET; see the link below) with a response scale anchored by terms like "Poor", "Average", "Superior" "Outstanding (top 10%)" "Top 1%" (you will need more anchors at the "top end" because performance tends to be very skewed).
If that's not feasible, you could have project teams complete the same ratings. There is some evidence that such peer reviews can be effective (less good than managers' ratings, but still valid and having the advantage that you can average the ratings of several people).
The other answer to your question is that there is a project management certification test. You won't be able to access their item pool (I assume) but you might find practice exams that you can use to measure project management knowledge as a proxy for project success. The second link below was something I found in a quick search (i.e., I have no idea whether it's good or not). A problem with this approach is that knowledge of project management is not the same as project success and may not have very high correlations with emotional intelligence. Probably (I'm guessing) that it would have a higher correlation with EI measuring using an "ability model" (like the MSCIET) and lower correlations with "trait model" (using Likert responses).
The idea of project prosperity or success is too challenging to define you may follow PMBOK (PMI, 2013:35) contends that: ‘Since ventures are impermanent in nature, the victory should be of the measured in terms of accomplishment of the venture inside the requirements of scope, time, cost, quality, resources, furthermore dangers are approved between the venture supervisors and senior management … venture achievement are ought further strengthen a chance to continue to the final baselines affirmed by the commissioned stakeholders and the project manager who are mindful and responsible for setting realistic, attainable and achievable limits to the venture to fulfill the venture inside the sanction baselines’.
In agreement with previous respondents, traditionally, project success has been measured based on the famous “triple constraints” or “the iron triangle” of time, cost and scope of objectives. These elements are interdependent; a little change to one will affect the other. Others authors added clients to the triangle.
A few writers basically believe that everybody knows what is meant by project success and project disappointment. What is known though in project management is that the accomplishment is an ambiguous, inclusive, also multidimensional idea whose definition will be bound to a particular setting.
I am not sure whether the questionnaires used in the first article have been validated and proven to be reliable but at least those questionnaires may provide a peer-reviewed source for your use. The second article may also be of use ... at least I hope so.
a project is under taken with aim of achieving both objective and subjective function. so we have to explore the alternative methods of determining project success beyond the traditional means of evaluating project success. a balance score card approach developed by Robert Kaplan has emerged a good measure to measure project success. we have to develop project outcome metrics based on how an experienced project stake holders evaluate the characteristics of project success, both objectively and subjectively rather than exclusively relying on externally established criteria that may not reflect project stake holder’s view of the outcome in the context of the performance challenges, strategic objectives or the marketplace” following link may be helpful to you for deeloping construct