A challenge in project management in a multi-project environment concerns sharing human resources across projects. Generally, project-based organizations share resources to regulate and plan the project portfolio. This resource allocation process can be elevated through the estimation of required resources by assessing different strategies. Two strategies, static and dynamic, have been applied for resource allocation and compared project performance during this work. Our contribution focuses on how a resource-constrained and schedule-constrained project management policy can meet the planned project performance. Switching resources through dynamic allocation ensures that a project can be delivered on time even when there is no free resource capacity and hiring new staff. Besides, productivity changes as resources are switched among projects back and forth by exploring the gap between the actual and the expected completion dates that affect project performance. Three example projects portfolio has been analyzed employing a system dynamics simulation model. The aim is to plan and control the projects’ progress in a multi-project environment by analyzing human resources changes, which will help portfolio managers decide optimal resource allocation.