"Improved test depth" in automated testing means:

1. _Thorough examination_: Automated tests can thoroughly examine device functionality, exploring multiple layers and scenarios.

2. _Deeper fault detection_: Automated tests can detect faults and errors that may be missed by superficial testing.

3. _Increased test complexity_: Automated tests can handle complex test scenarios, simulating real-world conditions.

4. _Multi-layer testing_: Automated tests can test multiple layers of device functionality, from hardware to software.

5. _Edge case testing_: Automated tests can thoroughly test edge cases, ensuring devices operate correctly in extreme scenarios.

6. _State machine testing_: Automated tests can thoroughly test device state machines, ensuring correct transitions and behavior.

7. _Error propagation testing_: Automated tests can test how devices handle errors, ensuring proper error handling and recovery.

8. _Robustness testing_: Automated tests can test device robustness, ensuring they operate correctly under stress and unexpected conditions.

Improved test depth in automated testing ensures devices are more thoroughly exercised, increasing confidence in their functionality and reliability.