The study intends to identify the existing implementation bottlenecks that hamper the effectiveness of the Ethiopian forest policy and laws in regional states by focusing on the Oromia Regional State. It attempts to address the question, "What are the challenges for the effective implementation of the federal forest policy and law in Ethiopia in general and Oromia Regional State in particular?". The study followed a qualitative research approach, and the relevant data was collected through in-depth interviews from 11 leaders and experts of the policy, who were purposively selected. Furthermore, relevant documents such as the constitutions, forest policies and laws, and government documents were carefully reviewed. Based on this, the study found that there is the dichotomy between the provision of the constitution regarding the forest policy and lawmaking and the constitutional amendment on one hand and the push for genuine decentralization in the Ethiopian federal state on the other. To elaborate, the constitution is rigid for amendment, and it has given the power of forest policy and lawmaking to the federal government. On the other hand, the quest for genuine decentralization requires these powers to be devolved to the regional states. As the constitution is rigid, this may continue to be the major future challenge of the forest policy and lawmaking of the state. This demonstrates a conflict of interests between the two layers of governments, i.e., the federal and regional (Oromia Regional State) governments. Respecting and practicing the constitution may be the immediate solution to this pressing problem.

Delay is the leading challenge in completing Engineering, Procurement, and Construction (EPC) projects. Delay can cause excess costs, which reduces company profits. The relationship between subcontractors and the main contractor is a critical factor that can support the success of an EPC project. The problematic financial condition of the main contractor can cause delay in payments to subcontractors. This research will set a model that combines the system dynamics and earned value method to describe the impact of subcontractor advance payments on project performance. The system dynamics method is used to model and analyze the impact of interactions between variables affecting project performance, while the earned value method is applied to quantitatively evaluate project performance and forecast schedule and cost outcomes. These two methods are used complementarily to achieve a holistic understanding of project dynamics and to optimize decision-making. The designed model selects the optimum scenario for project time and costs. The developed model comprises project performance, costs, cash flow, and performance forecasting sub-models. The novelty in this research is a new model for optimizing project implementation time and costs, adding payment rate variables to subcontractors and subcontractor performance rates. The designed model can provide additional information to assist project managers in making decisions.