When developing requirements for a business process in which there are valid process variants, one usually describes the process variants as a behavior. When modeling these variants, it is useful to consider each aspect of a process that has variants, and isolate unique behaviors based on some decision framework. Both the distinct list of behaviors (behavioral taxonomy) and the attributes driving the decision framework (driver mapping) are important to the model.
The list of behaviors is important, because the words that identify each behavior become important words in the language used to describe your business process. When you talk about these behaviors, you all (technicians and subject matter experts) can use the same unambiguous terminology to describe the process.
Sometimes in the business process documentation, the language is about the steps and the business rules that govern each step. At a higher level of abstraction, we benefit from aggregating these business rules into patterns, or behaviors that have some cohesion around a small number of attributes or facts. When we observe these patterns, we can simplify the language around the business process, by naming the distinct patterns as specific behaviors, and identifying them with a business driver as observed in the attributes.
When we isolate and name the patterns as specific behaviors, we also can understand the data elements or attributes and values that drive the decision framework. This mapping of data elements and values to select a behavior is also part of the requirements, as it is important to ensure that all valid values for each attribute are considered in the behavior selection.
More complex processes may have several different aspects that are governed by distinct behavioral taxonomies, and isolating these taxonomies from each other is important. Sometimes when we try to render a single behavioral taxonomy that governs a process, and find that we cannot easily recognize the behaviors, we actually have a more complex case, where there are nested behavior variants, or we have non-correlated (independent) behaviors governing several aspects of a process. In these cases, if we isolate the individual lists or taxonomies of behaviors, then review against each other to determine whether relationships exist between taxonomies. Those relations can be classified as governing hierarchies (where available selections in one taxonomy are limited by the selection in another "governing" taxonomy.), or incidental constraining relations (where as it happens, the selection of a behavior in one taxonomy, either requires or invalidates one or more behaviors in other taxonomies, but those constraints are not imposed exclusively in any one direction between two taxonomies)
Clearly identifying the distinct behaviors of the business process, and the data elements or attributes that can be used to select each behavior supports a good requirements modeling practice.