The second component of rationality is instrumentality. 1 Many empirical researchers are actually engaging in rational choice modeling without necessary realizing it. However, both logistic regression and probit assume an axiomatic utility model. Many researchers use techniques such as logistic regression and probit (or the multinomial versions of these techniques) to study the effect of various factors on vote choice. It should be noted that the statistical methods used by many voting behavior researchers implicitly assume this kind of consistency. After all, consistent patterns are being searched for when trying to explain how people vote. However, if voters’ choices are not consistent as a rule, it is very difficult to see how they could be modeled effectively. Of course, it may be the case that sometimes voters’ preferences are not consistent empirically. When discussing “utility” it is not necessary to believe that such a thing exists in a metaphysical sense but instead just to claim that the alternatives can be rank ordered consistently. If I then put a number on each line, I have a simple utility function. I can take a piece of paper and write the thing(s) I like most on the first line, the thing(s) I like second best on the second line, etc. This amounts to saying that I can rank order the various things I have to decide between. Furthermore, if I prefer apples to pears, and prefer pears to peaches, then I must prefer apples to peaches.
For example, in deciding between apples, pears, and peaches, I need to have a preference between each of them, or at least be able to say that I like them equally. Choice is consistent if it is possible to rank all alternatives in a transitive way. No judgement is made as to whether this end is normatively desirable. A choice is rational if it is the best way of achieving a certain, logically consistent end. Rationality consists of two components: Choice must be consistent and it must be instrumental. However the definition of rationality in rational choice is very minimal. The word “rational” is highly loaded normatively. To consider the application of rational choice to individual voter behavior, it is first necessary to define what we mean by rational choice. In fact, they are assumptions made in a great deal of research in voting behavior, including that by many researchers who do not think of themselves as doing “rational choice.” It is when we consider collective choice that rational choice models yield results that are both more controversial, but also potentially fruitful. The assumptions of rational behavior on individual choice, while not completely uncontroversial, are rather mundane. On the other, we can take a macro view and consider the effect of rational behavior on aggregate choice. On one hand, we can look at the micro level and consider the effect of assuming rationality on individual voting behavior. We can distinguish between rational choice as a theory of individual choice and as a theory of collective choice.