Guide for Establishing a Theory of Probable Cause

CompTIA A+ troubleshooting methodology includes a step known as Establishing a Theory of Probable Cause.

What is it?: A Theory of Probable Cause is essentially a hypothesis of what is causing the problem in a given IT context. This involves gathering information, identifying symptoms, and using your knowledge and experience to pinpoint the most likely cause of the issue.

Why it is important?: This step is critical as it helps in saving time by providing a focused approach to troubleshooting. It also reduces the risk of causing additional problems by making unnecessary system changes.

How it works?: After gathering all the data about the issue, you create a short list of the most likely causes. You then test these theories one-by-one, starting with the most likely and eliminating them until you find the root cause.

Exam Tips:
- When answering questions around this topic, have a systematic approach in your mind.
- Read the question carefully to identify the problem, gather clues from the information provided, and apply your technical knowledge to establish a probable cause.
- Use elimination to narrow down to the correct cause.
- Show your working in exam questions where you need to establish a theory of probable cause. This demonstrates your systematic approach even if the final answer is incorrect.
- Remember that this phase is a part of a larger troubleshooting process. Understanding the overall process will help you answer the question in the context of the steps that come before and after it.