The history of unconstraining models in revenue management

Unconstraining has been used in revenue management (RM) for nearly the last 40 years. This brief, historical article surveys over 40 articles from the recent period and traces the evolution of RM unconstraining models. The two main areas that are covered are general articles comparing the performance of different unconstraining methods under a variety of circumstances and more recently, customer choice models related to unconstraining censored data.