Diagnostics are engineering and operations analysis programs used on all Starfleet ships, stations, and installations. Starfleet uses a standard diagnostics scale of 1 to 5. 1 being the most comprehensive examination of the system while a level 5 is a fast, automated examination. Diagnostics programs are pre-programmed system analysis programs and carry out an automated determination of system performance and at the same time identifies any malfunctions.

Level 5 Diagnostic 

This is an automated procedure that is mostly intended for routine use to verify system performance. Level 5 diagnostics require usually less the 3 seconds and are typically performed on all systems at least on a daily basis. Level 5 diagnostics are also performed during crisis situations when time and system recourses are carefully managed. During a Level 5 diagnostic, the system may remain On Line.

Level 4 Diagnostic

A Level 4 diagnostic is an automated procedure used whenever trouble is suspected with a given system. The protocol is similar to a Level 5 but does involve a more sophisticated analysis. A Level 4 diagnostic is also used during a shift change in order to generate an accurate report for the duty officer. During a Level 4 diagnostic, the system may remain On Line and can be performed in under 30 seconds.

Level 3 Diagnostic 

A Level 3 diagnostic is a protocol very similar to a Level 1 and Level 2 diagnostics but also involves crew verification of key mechanics and system readings. This is a complete scan and is only used on computer systems. During a Level 3 diagnostic, the system may remain On Line and can be performed in 10 minutes or less.

Level 2 Diagnostic 

A Level 2 diagnostic refers to a comprehensive system diagnostic protocol which, like a Level 1 diagnostic, involves a very extensive automated routine but also requires crew verification of most operational systems. A Level 2 diagnostics takes around 1.5 to 2 hours and does require the systems to be taken off line before any tests can be performed.

Level 1 Diagnostic 

A Level 1 diagnostic is the most comprehensive type of system diagnostics. Extensive automated diagnostic routines are performed but a team of crew members is required to physically verify the operation of system mechanisms and system readings. A Level 1 diagnostic takes around 2 to 3 hours and requires the systems to be taken off line during the tests.