This chapter offers a reflection about systems thinking, models and validation tests. In this way, starting from the recognized model of information systems success created by DeLone and McLean, the authors develop an adaptation in the executive information systems (EIS) area. Their research aim is to carry out a validation test of the adapted model applying the Partial Least Squares approach. The study is based on a survey involving 100 managers in 55 Spanish organizations. The results show this model has an adequate predictive power for most implied variables, demonstrating the existence of significant links among information systems success dimensions. The model helps to understand the influence of EIS on both individual and organizational impacts. Finally, as a consequence of the validation process, new ideas for the redesigning of the model are proposed.