Once the decision to staff a position has been made, and once it has been posted publicly, it takes an average of 197 days to hire a new employee. Prior planning of human resources remains necessary to ensure that the available resources are taken into consideration and that the manager choses the right staffing tool. All of that work must be done upstream. You are correct to say that the process is more complex than what we measure.
We chose to establish that starting point and that end point for our calculations. Afterwards, we will need to establish a baseline. Finally, we will see what improvements need to be made to the process in order to shorten some steps.
A lot of people are participating in the process, at each step. The hiring manager has a role to play. Human resource professionals provide advice. There is also the Public Service Commission. There are others involved, like the people who are responsible for security in the departments. So there are a lot of stakeholders. Aligning all of these stakeholders to work together on a strategy to rationalize the process represents quite an effort.