Classical functional analysis has the following components:
1. Identify potentially relevant characteristics of the individual client, his or her behavior, and the context in which it occurs via broad assessment. The purpose of the step is simply to collect data from which the beginnings of analysis might emerge. Exactly what occurs at this step is dictated by the philosophical and theoretical assumptions (usually implicit) of the assessor and informal prejudgments made about the case based on referral information, preliminary interviews, and the like.
2. Organize the information collected in Step 1 into a preliminary analysis of the client's difficulties in terms of behavioral principles so as to identify important causal relationships that might be changed. The process of functional analysis has been described as a funnel (Hawkins, 1979). The opening is wide at the top but then begins to narrow down. Step 2 in functional analysis, traditionally conceived, is to begin to narrow the focus of assessment. Certain features (e.g., forms of behavior, motivational operations, contexts in which behavior occurs) are tentatively selected as more important than others. Characteristics of the case are organized into classes. The guiding principles are behavioral in the catholic sense of that word, but with a special emphasis not simply on the structure of the phenomena observed but on their function -- what they do or affect in a dynamic system.
3. Gather additional information based on Step 2 and finalize the conceptual analysis. As features of the case coalesce, additional information is gathered relevant to the analysis. Specific assessment devices may be selected or created to examine particular features of the case as conceptualized in Step 2. In this process, the analysis may be refined and modified. Eventually the assessor has a stable conceptual analysis of the relation between actions of the client and its context, with measurement data on the primary components of that analysis and assessment procedures in place for a continuing evaluation of the case.
4. Devise an intervention based on Step 3. One dominant characteristic of behavioral assessment is the close link, at least conceptually if not often empirically, between assessment and treatment. Because behavioral principles are explicitly pragmatic (their confirmation is usually based on the ability to predict and influence behavioral events through their use), a functional analysis often points to concrete events in the life of the clients that have established and are maintaining the problem of interest. If these events are manipulable in the practical world of clinical intervention, a thorough-going functional analysis often directly suggests a particular intervention. Thus, in Step 4 a treatment is devised that is linked to Step 3.
5. Implement treatment and assess change. Assessment, to most behavioral assessors, is not something done only at the beginning of treatment. It is an ongoing process. Thus, a functional analysis contains within it the ongoing assessment of clients' progress.
6. If the outcome is unacceptable, recycle back to Step 2 or 3. If treatment is not successful, usually this is taken as an indication that the conceptualization phase of the functional analysis itself is flawed. Thus, a failure to see the kinds of changes that are desired leads directly to a reexamination of the conceptualization, either in the form of a minor adjustment or, at times, a complete overhaul of the analysis.
ACT and RFT are fully compatible with this approach. RFT provides a generic functional analysis of relational operants, and ACT provides a generic functional analysis of some of their impact, but you still need to fit this into an overall functional analysis of the problems you are working with, some of which may be based on direct contingencies.