An operationalization of opaque serial depth

Currently, chain-of-thought (CoT) is a valuable tool for overseeing AI models. However, some architectural shifts could significantly reduce CoT monitorability . We have recently proposed that AI companies should transparently share ​​information about the degree to which their architectures may allow for latent reasoning and communication. To assist with this proposal, this document operationalizes a measure that serves as a proxy for the amount of unverbalized serial cognition a model can perform. Our measure is a specific instantiation of the notion of “opaque serial depth”, originally defi