Likert claims that his System-4 model fulfills all the above specifications. It has been defined by a limited number of key human organizational dimensions. These dimensions have been identified after extensive research and were found to be correlated with performance across a wide variety of organizations. Efficient instruments are available to measure the key dimensions of any human organizations. A sizable number of studies in different kinds of work situations have found that as organizations shift closer to System-4, there is a corresponding improvement in performance and increase in other desire results. To Likert, another useful aspect of the System 1-4 models for human resources development purposes is the recognition that certain human organizational dimensions are causal in character. Causal variables are those which are capable of being influenced or altered by the leadership and which, when altered, produce corresponding changes in the intervening variables and, in turn, in the results that the organization achieves.