I have never worked on a project where there are multiple project managers. However, I think having more than one project managers could be useful in certain cases such as when development projects run astray/run into issue and help is needed or in non-IT companies, where there could be two project managers, one is from the business side and the other is the technical project manager. Although having more than one project manager can be useful at times, I think it should be used as a last resort when having one project manager proves to be insufficient and dysfunctional and this decision should be handled with caution.

I found these articles helpful:
http://www.techrepublic.com/article/proceed-with-caution-when-assigning-additional-project-managers/
https://www.whizlabs.com/blog/how-do-you-handle-having-two-project-managers-working-on-the-same-project/

I have never worked on a project where there are multiple project managers. However, I think having more than one project managers could be useful in certain cases such as when development projects run astray/run into issue and help is needed or in non-IT companies, where there could be two project managers, one is from the business side and the other is the technical project manager. Although having more than one project manager can be useful at times, I think it should be used as a last resort when having one project manager proves to be insufficient and dysfunctional and this decision should be handled with caution.

Useful articles:
http://www.techrepublic.com/article/proceed-with-caution-when-assigning-additional-project-managers/
https://www.whizlabs.com/blog/how-do-you-handle-having-two-project-managers-working-on-the-same-project/

Although I have never worked on a project where there are multiple project managers, I think having more than one project managers could be useful in certain cases such as when development projects run astray/run into issue and help is needed or in non-IT companies, where there could be two project managers, one is from the business side and the other is the technical project manager. Although having more than one project manager can be useful at times, I think it should be used as a last resort when having one project manager proves to be insufficient and dysfunctional and this decision should be handled with caution.

Useful reference:
http://www.techrepublic.com/article/proceed-with-caution-when-assigning-additional-project-managers/
https://www.whizlabs.com/blog/how-do-you-handle-having-two-project-managers-working-on-the-same-project/

Reference: http://www.techrepublic.com/article/proceed-with-caution-when-assigning-additional-project-managers/
https://www.whizlabs.com/blog/how-do-you-handle-having-two-project-managers-working-on-the-same-project/

Had issues with attaching references and additional articles

About 6 months ago when I worked in validation, mw group worked on a project where we did a media simulation in collaboration with the manufacturing department. There were one other group managing that project and it was the first time we were performing it with this group. In the initiation phase the group got together and determined what needed to be accomplished and the time line for our deliverables. We planned out how we can meet our goal be determining a schedule for the performers and what resources and documentation we would need. In our case that part went reasonable well, until we got to the execution phase where we realized that that we did not account for human error in the planning phase. Working on project with manufacturing require that we follow GmP with no exceptions. We outsourced another company to check all the samples that were filled into vials to verify that the sterility requirement was meet. We ran into a lot of problem with the consistency on the labels and the documents that were going to the other company being correct. This was due to a lack of communication between departments and resulted in some delayed in the project. Once we realized this we went back to the planning and was able to get back on track.

Most of the projects that I have worked on, which have had a big scope and long timelines, has followed a format in which one person is the Project Manager and underneath the project manager are a bunch of Project Leads from different departments. The Project Manager usually has a high overview of the details of what is going on within the project that is usually reported to him/her through the Project Leads. The Project Leads are basically the leaders or head of whatever department in the supply chain that is involved with the project. Most of the major projects I've personally worked on are driven by Regulatory (UDI / BSI), therefore they are the project managers. Then the Project Leads are people within Manufacturing Engineering, Supply Chain, and Finance. Most of the people doing the executing of the project are actually the people who work beneath or alongside the Project Leads such as the analyst, specialist, or lower level engineering roles. When it comes time to reporting to upper management the ins and outs and anything good or bad, the Project Manager usually ends of taking a lot of the heat.

When I was working on BSI (basically the FDA of Europe), this project pertained to meeting certain European regulations and the Regulatory people within the company had weekly meetings essentially with the BSI auditors and upper management. Therefore, it makes sense that these people would be the Project Managers. Ideally, whichever department has the most at stake for the project, should take ownership of it.

While working at General Dynamics Electric Boat, I worked on several projects that had different project managers for different portions of the job. There are pros and cons to this approach. The good thing is that people are experts on their portion and have more experience and insight. This helps to foresee problems and mitigate them. The bad thing is that there is no real ownership. Yes, people are assigned this or that but they are working on lots of different projects and at the end of the day, only one manager is really responsible for it. Due to there being no real ownership, some managers might not take deadlines as seriously and there is conflict.

When I worked in the industry, I met the situation that there are multiple project managers. I think it is much better than only one manager. Since everyone has their strong points and weak points. Multiple managers help to avoid the project failed because of the misleading of the managers. They can discuss with each to help solve the problems.

I have not worked in a project having multiple project managers either, but I do feel that it may be an effective method to getting a project completed. With multiple project managers, there come different ideas from various people. In addition, sometimes on certain projects, there may not be a good project manager. However, with multiple project managers, there would be different views to consider to ultimately create the best product. On the other hand, I do feel that having multiple project managers will cause more confusion in the project. Although everyone’s role will be defined, people still may feel some leniency as to who reports to whom. I agree with you that having multiple project managers should be considered only if necessary. Having only on manager will allow for a more assertive decision making.

I have never worked on a project where I have two project managers, but I am currently experiencing a similar situation where I have two managers in a lab and trust me it's really helpful when you have two managers. Both of my managers are really friendly and amazing so if I have any question any time I can go ask either one of them. And I think the project become more fun and easier to manage when you have two managers and most importantly their is an additional opinion which might make the project more successful.

Although I do not have industry experience, my (limited) experience in working with hierarchical groups leads me to believe that having multiple managers can sometimes be a recipe for disaster. Being a manager promotes a sense of responsibility. A project manager for the "X Development Project" knows that, at the end of the day, he is responsible for the deliverable "X," and that he cannot blame his (or her!) subordinates for failure to do so. A singular manager also helps avoid conflict. When there exist multiple managers with equivalent authorities, fights between can be long and destructive, as there may be no direct authority figure able to intercede and force a truce.

The benefits of a system with multiple managers, in my opinion, are vague. Multiple managers may bring different strong points, yes, but the point of a good manager is to understand the project as a whole and assign subordinates to tasks based on their strengths. A good manager can manage a hierarchy of people with varying skillsets, assign those people based on where they are needed, and mediate any conflict that may develop between them. As Scott mentioned, under a top-level manager are sub-level managers. This hierarchy, when well-implemented, will provide the benefits of having multiple managers without the drawbacks.

In my opinion, multiple project managers for a single project is not an ideal solution. Multiple managers would involve multiple behaviors, acceptance on a single solution for a part of project is difficult, bringing all the managers to accept a unique point of view. In my past company, we had multiple managers to report on a project. They both were so different personality making the project team difficult to provide solution. One manager used to agree for the solution whereas the other disagreed. This caused project delays, confusion and no success. Eventually the project had to be called off and management later decided to assign a single manager for a single project.