CompTIA publishes this methodology in its A+ exam objectives as a best practice for new technicians. (For the 220-1200 series, CompTIA notes the method itself is not tested but is part of the competency standard.)
- Identify the problem. Ask what happened, when it started, and what changed. Reproduce it if you can.
- Establish a theory of probable cause (question the obvious). Research the knowledge base or internet if applicable.
- Test the theory to determine the cause. If it is not confirmed, form a new theory or escalate.
- Establish a plan of action to resolve the problem and implement the solution.
- Verify full system functionality and, if applicable, implement preventive measures.
- Document findings/lessons learned, actions, and outcomes.
Worked example: “The internet is down”
- Identify: one user, wired desktop, started after the desk moved.
- Theory: the cable or wall port (question the obvious).
- Test:
ipconfig /allshows a 169.254 address, meaning no DHCP lease (ipconfig). Swapping the patch cable restores a normal address. Confirmed. - Plan and implement: replace the cable; label the port.
- Verify:
pingthe gateway and load a website (ping). - Document: note the bad cable and the port in the ticket.
Source: CompTIA A+ 220-1201 Exam Objectives (v2.0), “Troubleshooting methodology knowledge”. Step wording quoted from that document. Checked 2026-10-16.