Abstract: A method and apparatus are disclosed for validating recommendations generated by a television program recommender using programmed viewing agents. A viewing agent is programmed with a set of rules that characterize the viewing preferences of a modeled viewer. During a training phase, the programmed rules of a viewing agent are applied to a set of training programs to obtain an agent viewing history. The method and apparatus estimates the required size of the viewing history to provide a given level of accuracy. The viewing agents can be programmed to introduce one or more random shows into the viewing history, or to change the preferences of the viewing agent over time, thereby allowing the television program recommender validator to evaluate how the program recommender processes such non-stationaries.