A three-dimensional conceptualization or hypothesis-testing research designs A conceptualization of research designs for hypothesis-testing research is proposed in terms of four facets or dimensions, namely, unit of analysis (individuals, households, gangs, riots, journal articles, etc.), the presence or absence of an intervention to elicit the relationship to be studied (experiment or survey), research setting (laboratory or field), and measurement or data collection procedure. When the unit of analysis involvesindividuals, the choice of level of any of the other three facets does not, by definition, restrict the choice of the levels of the remaining two facets. Consequently these facets may be represented graphically by a three-dimensional block. For example, experiments are not necessarily restricted to laboratories in which data are collected by obtrusive measurement Instead of restricting the description and classification of research designs in terms of their typical utilization in the past, this conceptualization has the advantage of facilitating a more complete understanding of various designs and exploiting the full spectrum of possible designs. Factors which thwart or prevent the realization of some combinations of levels of the above facets are indicated.