The RSA has overall responsibility for the operation, oversight, development, quality assurance and delivery of vehicle testing arrangements.
I understand from the RSA that pass rates vary, to some degree, across the network, particularly depending on the average age of vehicles tested, their mileage, maintenance and condition of local roads. The level of preparation of vehicles is also a major factor in determining the likelihood of passing the test.
The RSA has always recognised the need for consistently high vehicle testing standards no matter which test centre, or which Vehicle Inspector, conducts the test. All Vehicle Inspectors are fully qualified and experienced mechanics. Also, the NCT testing system is computer-controlled and highly automated and provides maximum test security, accuracy and consistency. Uniform standards are set for what is tested, how the test is carried out and the reasons for failure. The NCT system stands up well to international benchmarking in this regard.
In addition, the testing system and Vehicle Inspectors are subject to a very stringent audit system which is carried out independently by the Automobile Association on behalf of the RSA. All test centres receive frequent unannounced visits, during which independent re-inspections of vehicles are carried out and Vehicle Inspectors are observed undertaking tests. These show that over 98% of tests are correctly assessed.