The D. Lerner and W. Schramm model of the role of mass media in national development has influenced most media oriented studies of development for almost two decades. Briefly, the model suggests that the evolution from traditional to modern societies follows a causal path that leads to increased mass media use. The path ends with increased political participation and growth in gross national product (GNP). A study was undertaken to test the validity of the Lerner-Schramm model using new data drawn from the 1970s and from more sophisticated modeling techniques. In addition, three expanded models that incorporate new variables suggested by economists and other theorists--industrial base, physical quality of life, and horizontal media (telephone, mail, and telegraph)--were used. No evidence was found to support the Lerner-Schramm hypothesis. Mass media also had no influence on political participation or on physical quality of life in the expanded models. There was a significant relationship between mass media and GNP growth, though not in the direction suggested by Schramm and others. There was also some evidence showing a relationship between telephone saturation and increased political participation, lending support to Frey's contention that horizontal media may be more influential than other media in loosening government control in less open societies. Results suggest the need for a more thorough examination of the assertion that the key to development is equality of distribution of information and socioeconomic benefits. (Author/FL)