Having a structured approach to solving problems will help you resolve them more quickly and directly. Guessing the cause of the problem rarely works. You want to not only resolve this particular problem, but you also want to understand the problem well enough so that you can identify the root cause and ensure that this particular problem does not occur again.
1. Identify the problem or symptom
You should not assume that everyone knows the problem already. Take the time to document the problem in clear terms that everyone can understand. If you cannot clearly document the problem, it will be difficult to solve it. Make sure that you also explain the impact of the problem to the project.
2. Identify the root cause (or causes)
This is the most important step, since you do not want to spend your time resolving a symptom that you think is a root cause. Instead you should be very clear on the root cause and explain how the root cause ultimately results in the problem. If you cannot track the root cause to the perceived problem, you have not taken your investigation far enough. There are a number of issues management techniques that describe how to focus in on the root cause.
That being said, it may be that the root cause is not within your power to resolve and you may be forced to try to solve a symptom. However, you want to still be sure to identify the cause(s) of the problem to make sure you understand if you are solving a cause or a symptom.
3. Determine alternatives and impacts
The project manager may assign one or more people to determine alternatives. For each alternative, they should also address the impact to the project.
4. Select the best alternative
The project team and appropriate stakeholders can all be involved with determining the best alternative. This may include members of the project team only, or outside stakeholders.
5. Resolve the problem
A plan is put into place to address the problem and implement the chosen alternative. This could just be one activity or it could be a complex plan of resolution. These activities should be moved into the project schedule to ensure that they are performed
6. Validate the problem is resolved
The situation must be monitored to ensure that the problem is resolved as expected. If the problem appears to be resolved you are done. If the problem or a related symptom still exists, you have more work to do. Return to step 1.
Source: Method 1 2 3...empowering managers to succeed!