People with a strong creative principle (generators of ideas) are involved in the main developments due to their ability to think, but they are impractical and often cannot make the right decision. While in an effective group, the conductors are the ones facing the most ideas put into practice (Belbin called Workers as performers). Their main advantage is the ability to achieve their goals, achieve results. They trust people who have a high degree of integrity, but also like to have the control. An effective group also needs an intelligent, shrewd and sober minded person, who is able to give a correct estimate of the ideas emanating from the generator of ideas. This role – the role of criticism, is executed by an observer/Estimator (Rosemary, 1996).