The Early and Middle Formative periods, as I define them here, correspond to the Early, Middle and Late Chiripa phases as defined by Steadman (1999). The many attributes employed by Steadman include paste, firing, slip, finish, rim form and diameter, and decoration, among others. Each phase is identified by a particular combination of attribute ranges. The key point here is that there are very few attributes that are unique to any given phase. A particular paste, for example, will be most common (say 40%) in one phase, but will also occur in lower frequencies (say 5-10%) in other phases as well. Of the few attributes that are truly diagnostic or phase-specific (such the neckless olla form for the Early Chiripa phase [[Steadman 1999]: 62-63 and Figure 22]), all are quite rare, so that they may be observed on only a small percentage of an assemblage. This means that while Steadman's chronology is quite directly and easily applicable to unmixed assemblages (assemblages representing a single phase), it is more difficult to apply to mixed assemblages. Since the vast majority of the Early and Middle Formative Period sites encountered in the survey were multi-component, I was forced to devise a method for distinguishing relative percentages of phase-specific attribute frequency profiles in mixed assemblages. I term this method frequency profile analysis.