"I'm not sure OSM improves accuracy"
When marking paper-based scripts, AOs have to wait until the scripts are returned from the markers for review. It is only then that issues may materialise about marking quality. OSM allows an Assessment team to monitor marking in a live environment and address issues mid-stream. In addition, OSM allows for seeding of profile responses to flag marking quality issues. OSM allows for item / question level marking which has been proven to improve reliability of marking by allocating more difficult questions to more experienced markers for better consistency. Item level marking can also help to reduce the “halo effect” (marking influenced by the quality of answers on other questions on the same script) and potential examiner biases.