Do you recognize that project managers complain that they do not get the resources they have been promised, while line managers blame the fact that they do not know when the resources will be available. It's a real Catch-22 that is completely unnecessary when there is a simple solution to the problem of resource planning.
The solution is to start from LEAN and plan occupancy with demand from teams and projects. Having all projects and resource utilization in one system creates the necessary transparency and decision support for decision makers to have full control over the occupancy consequences of already decided projects.
To achieve sustainable resource planning, it must be based on each individual's working hours and total commitment. Each task and activity implies a workload that must be accommodated within working hours each week. We talk about self-leadership - to realize it, we have to start from the individual's self-evident commitment and promise, which is to participate and use their skills where they are needed. Our solution means that the individual can negotiate and plan their working time with those who have a mandate to book working time from employees. There are project managers with a decided budget, team leaders who will staff teams and line managers with a budgeted activity over time.
A project manager should always present a complete plan to complete their project by the last hour. A line manager's task is to confirm the planning that the project manager and employees have already done together. Through digitization based on occupiable working hours, deviating planning against a resource budget can be immediately detected and corrected. The project manager can supplement the planning and, if necessary, bring in new resources via a dialog that shows who has the right skills and has unplanned working hours. A project manager can look for people with the right skills and with remaining unscheduled working time for each individual week in the calendar.
When all resource needs and working time are in one system with a simple planning model 'Plan Participation', there is always access to the current utilization of resources with available capacity to plan directly or as competencies.
Having all working time in one and the same system is an absolute necessity to have full knowledge of the organization's activities. What nobody spends time on does not exist. What someone spends time on must at least have a recipient, budget and timeframe. If you want to know who is responsible for a portfolio or an assignment/project, all you have to do is follow the money to the person who owns the budget that finances it.