Hospital effectiveness is a topic of great importance in public sector management. This article focuses on group effectiveness in Intensive Care Units (ICUs) in 44 Norwegian hospitals. The effectiveness of ICUs is for many patients a question of life and death, and the staff members should be trained to work under time pressure in extremely difficult decision situations due to the patients' acute life-threatening conditions. It is argued that effectiveness in such work groups is positively correlated with the ICU's ability to organize information. An important conclusion drawn from empirical tests is that high performing work groups are organized by way of hierarchy combined with complementarity, and extreme formalization combined with a high degree of decentralization.