Outsourcing to suppliers with unknown capabilities

•The manufacturer’s decision might not affected by the number of suppliers in the pool.•The manufacturer’s decision might not affected by how the manufacturer updates its beliefs.•The manufacturer may be more likely to always audit under updating.

We investigate the make-buy decision of a manufacturer who does not know its potential suppliers’ capabilities. In order to mitigate the consequences of this limited knowledge, the manufacturer can either perform in-house or audit suppliers. An audit reveals the audited supplier’s capability such that the manufacturer can base the make-buy decision on the audit outcome; the manufacturer might also learn from the audit and update its beliefs about the capabilities of the unaudited suppliers. Interestingly, using a very general model we find that the manufacturer’s decision can be independent of both the number of available suppliers and of the mechanism it uses to update its beliefs after an audit. We illustrate our general model by considering a possible application, where a manufacturer is making the outsource-audit decisions when the suppliers are more cost effective. However, when outsourcing to supplier, the manufacturer would face the uncertainty of whether or not the delivered task can integrate well with the other parts of the project.