Message processing literature could conceptualize process in one of two distinct ways: a single over-time process as described by J. N. Cappella, versus several processes as described by D. K. Berlo. An examination of literature finds that theories are based on both forms of these over-time processes. However, operationalization rarely measures either type of process over time. That is, process approaches are more common in theory than in measurement. A breakdown of the dimensions of time appropriate to over-time research yields five specific dimensions: (1) the time-frame of the study; (2) the time-lag over which effects are measured; (3) the duration of the independent variable; (4) the duration of the dependent variable; and (5) the effect span. In order to improve scholarly research attempts at exploring over-time processes, the two distinct theories of process should be carefully considered, and these time-based dimensions should be carefully used. (Three figures and four tables of data are included; 193 references and four appendixes are attached.) (Author/SR)