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Where can you find the inputs?
A project management plan is a formal, approved document that defines how the project is executed, monitored and controlled. The project manager creates the project management plan following input from the project team and key stakeholders.
(as defined in Wikipedia)
Input is a term that refers specifically to any particular item, product, or mechanism that refers to an internal or external device that can be used for the purposes of triggering the progression of a particular process. This form of input is always a requirement before the process is actually able to proceed as such. Input can come in many different means such as such as specific types of data that can be entered into the system, the results of which can trigger the process to begin again. Input can be derived in many cases as a resultant output from a previous work schedule activity or a previous work process. Input can be the result of a compilation of various phases of a particular project, it could be the result of one specific work activity, or it can be data that is entirely independent of the overall project processes but no less essential to the continuing progress of the overall activity.
(as per Project Management Knowledge Definition)
Stakeholders are individuals and organizations who have a vested interest in the success of the project. The identification and input of stakeholders help to define, clarify, drive, change, and contribute to the scope, cost, timing, quality and, ultimately, the success of the project.
(as per here)
These are a couple of definitions you will find by simply browsing the Internet or by reading various books on the Project Management topic.
My conclusion: without proper input, you will get no real results. If the inputs are perverted (no matter the reasons), you will not be able to reach your goals.
I believe that the below graph summarizes this nicely:
plus it announces another good Project Management concept, Output!