NOSA follows the following process when conduction audits on clients' systems/standards:
Baseline audit:
This is the first audit NOSA conducts at the request of a client. During this audit, system deviations are identified and recommendations for further improvements are made.
Star grading audit:
This is an audit conducted to determine the status of a client's risk management system and compliance with the standard. This audit is conducted once a year or more frequently at the client's request. The result of this audit is displayed as a NOSA star grading. NOSA measures incident experience and effort during the grading audit. Outcomes are reached by measuring specific safety, health and environmental indicators.
The NOSA audit team makes every effort to provide an independent audit outcome to clients in the quest to uphold the best principles of risk management in everyday business operations.
Each applicable element of the system is evaluated during an audit, with criteria and percentage points allocated as follows for safety, health and environment respectively:
| Criteria |
 % Points |
| Hazards identified and risks assessed |
10 |
| Appropriate systems, standards, and procedures in place |
20 |
| Degree of compliance with above systems, standards, and procedural requirements |
30 |
| Overall effectiveness |
40 |
| TOTAL |
100 |
