Despite the contemporary and historical importance of sudden eruptions of popular opposition to constituted governments in Africa, the subject remains largely untouched by the kind of systematic analysis which might alert us to the possibility of similar occurrences in the future. This article presents a paradigm of political relevance designed to improve our ability to anticipate such events by showing how shifts of persons into situations of potential or actual relevance to modern politics may be traced through the use of quantitative data derived from social mobilization. Political change in Tanganyika (now mainland Tanzania), between 1947 and 1954, is used for illustrative purposes because it constitutes a classic example of how persons supposedly familiar with its politicsboth British administrators and nationalist politicians-consistently misjudged the potential for anticolonial protest before and after its emergence in 1955.1 I shall first explain the relationship between social mobilization and political relevance, describe the paradigm, and illustrate how mobilization data may be used to trace changes in the extent of popular relevance to mass politics. The paradigm will then be applied to Tanganyika's politics to show how it may enhance the realism of judgments about the likelihood of sizable shifts of previously apathetic persons into overt political activity and opposition. According to Karl W. Deutsch, social mobilization is inherent in modernization and is significantly related to political changes associated with the impact of the forces of change upon traditional societies. He terms this "an overall process of change which happens to substantial parts of