Minimum performance levels (MPLs) for the components of the CACO are predetermined and based solely on performance criteria. With this methodology, candidates attempt to meet or exceed the minimum standard of performance and do not compete against other candidates. As well, this methodology removes predetermined passing rates for the administration of the CACO. If the candidate population has a high level of performance on the assessment, the failure rate will be low. If the performance level of the candidate population on the assessment is low, the failure rate will be high.

MPLs are established in advance of selection for a CACO administration by groups of practising optometrists who evaluate and rate each question item to be administered using a generally accepted method. Each question is assessed using the following question: “What fraction of a group of minimally competent optometrists will answer this question correctly?” Consensus must be obtained within the group on a question for that question to be included within an examination. MPLs are not "adjusted" after the administration of an Assessment in order to achieve a particular Pass or Fail rate by the candidates.

The sum of the MPL values of all items in a given component becomes the Minimum Performance Level for that component. If a question is deemed to be difficult and likely to produce more incorrect responses, the question will lower the overall MPL. On the other hand, easy questions that are more likely to produce correct responses will raise the MPL.

This method is used to ensure that the standard for minimally acceptable competence is consistent as the question content of the CACO varies between administrations.