Although there have been frequent calls for over-time research in mass communication, there are still many reasons that researchers use simpler designs. Each approach: two-time point, panel/repeated measures, and time-series experimental designs, offers its own advantages and disadvantages. By examining the benefits and disadvantages of each approach and looking at several research questions, it appears that many research questions would benefit from using multiple approaches. A history of agenda-setting research suggests that non-theoretical over-time research may be a wonderful entry into questions of process, a place where theories may be developed. Theories allow these processes to be examined with other approaches. Therefore, examining temporal processes without developing theories, regardless of method, would be to the detriment of a researcher's ability to understand the processes and effects of communication. (Three figures are included and 123 references are attached.) (Author/MG)