This paper deals with the applicability of statistical principles and methods to research in political science. The subject is virgin and comprehensive. At the outset it will be necessary to delimit the treatment to be given it here, and to state some of the premises upon which this treatment will be based.
In the first place, the topic is unrelated to questions of public finance, or any of the bookkeeping aspects of government. I shall confine attention to more fundamental problems, distinctly psychological and sociological as well as political in character. These have to do with the nature and operation of forces that give rise to political activity and that determine its forms and its direction. A socio-political-psychology, quantitative in method, is the goal with respect to which orientation is sought.
In the second place, only data of a kind now available for research will be considered. Every statistician will agree with Professor Merriam's demand for the development and extension of governmental reporting, but my immediate concern is with undeveloped possibilities of utilizing existing materials.
In the third place, the desirability of a quantitative approach to political research problems is taken for granted. Yet the statistical method has serious limitations, not merely because it can never replace logic as a means of interpretation, but also because it is not universally available for scientific inquiry. The developments of recent years in the field of abnormal psychology, for example, have no quantitative method of discovery behind them. When subjective processes give rise to or accompany behavior, measurements of the latter may be possible.