There are 8 elements of reason, but often times we find ourselves using two at a go.
Purpose is the part of reasoning that tries to explain why an action is done. It clearly defines the reason why and establishes the aim of developing the case study. All reasoning has a key question, which defines the problem that is being solved. Purpose and key question are placed in one category because they both justify why a thought is being executed, and answering the question will bring out the purpose.
Information is very necessary in reason, since it provides the evidence and facts that will be used in figuring something out. Similarly, there are concepts, which are hypothesis or theories that will be applied in the problem solving (Rand & Peikoff, 1989). The two are categorized together because they both provide a means to the ends. The concepts are therefore part of the information.
A point of view is the place at which you view something from. You have to be at some position, naturally, for you to start reasoning. An assumption is the presupposition that is taken for granted. In any point of view, there has to be some assumptions, hence the reason of categorizing them.
Interpretations and inferences are the conclusions that you come to, based on the evidence. They are the judgments that come from the whole reasoning process. Implications and consequences are the truths that are elicited from other truth claims. Implications are as a result of thoughts, while consequences are a result of actions. The two are categorized together because the implications are a subset of interpretations and inferences, since they are both ends.
Rand, A., & Peikoff, L. (1989). The voice of reason: Essays in objectivist thought. New York: New American Library.