Information about delays can enhance service quality in many industries. Delay information can take many forms, with different degrees of precision. Different levels of information have different effects on customers and therefore on the overall system. To explore these effects, we consider a queue with balking under three levels of delay information: no information, partial information (the system occupancy), and full information (the exact waiting time). We assume Poisson arrivals, independent exponential service times, and a single server. Customers decide whether to stay or balk based on their expected waiting costs, conditional on the information provided. We show how to compute the key performance measures in the three systems, obtaining closed-form solutions for special cases. We then compare the three systems. We identify some important cases where more accurate delay information improves performance. In other cases, however, information can actually hurt the provider or the customers. © 2007 INFORMS.