How can I tell if I'm RLUEI or SLUEI?

This question (substituted with different SLOAN types) is possibly the most frequently asked question on the PDB big 5 forum. PDB users have a lot of difficulty understanding this issue because they assume that they can apply MBTI logic to SLOAN and that discovering their SLOAN type will follow a similar course to their journey to discover their MBTI type. The fact is that the two systems merely look similar. The differences in the underlying theory mean that the process to discover your type is completely different. Here are the three important points to bear in mind for those of you who are struggling with SLOAN because you are expecting it to behave in a similar way to the MBTI.

1. The Big 5 is Granular, not Combinatorial

If you use the MBTI in a dichotomous manner, I/E, N/S etc. then you are already using the MBTI in the same way as SLOAN works. The convention on PDB however is to calculate MBTI types via functions. With the function method, the change of a single letter can suggest a radically different type. For example an INTJ and an INTP do not share ANY functions in common out of their 4 function stack. If you expect SLOAN to work in a similar manner then it is reasonable to ask how an RLUEI and an SLUEI differ. It is reasonable to assume that there are many dramatic differences between these two SLOAN types. The reality however is that this is not how the big 5 works. The big 5 simply measures you on 5 different metrics. The independence of the big 5 traits is a core element of the theory. Because the traits are relatively independent, having a higher or lower score on one trait shouldn't have a meaningful impact on any of your other traits. We don't expect a person's eye colour to tell us anything about their age or vice versa. This is how independent traits work.

So the first thing to understand when asking a question of this nature is what question you are actually asking. Because the big 5 measures independent traits, you are not really asking about RLUEI vs SLUEI, you are simply asking about R vs S. As you are probably aware, this is simply a query about extraversion, nothing more. If someone knows that they are XLUEI then they simply need to think about their Extraversion in order to figure out their 2 point SLOAN type. It doesn't need to be any more complicated than that.

2. Tests are (essentially) Reliable

Due to the convoluted and unquantifiable nature of much of the fundamental MBTI theory it is hard to design a test that satisfies the demands of MBTI wonks. Perhaps the most oft-cited piece of received wisdom on PDB's MBTI forums is that "tests aren't reliable". We see this underlying assumption in evidence when PDB users beg other users for a big 5 analysis instead of simply taking a test. They have been told over and over in other forums that personality tests are unreliable and they now assume that having a brief conversation with a stranger will yield more reliable results than a lengthy and scientifically constructed test. The validity of tests is a core assumption in big 5 theory. The whole principle underlying the 6 facet model is that the 6 facets of each trait have been shown over and over to correlate in thousands of test results. There will always be issues with tests (e.g. the accuracy and honesty of the respondent) but similar issues will exist in other forms of analysis too. If you want to use the big 5 then your faith in the system necessarily must include some degree of faith that tests are a reliable form of evaluation. If you don't trust tests at all then there is no point learning about the big 5 because much of the theory is constructed from the results of thousands of tests. One of the main reasons why the big 5 is the dominant form of personality analysis amongst researchers is that tests have been shown time and time again to give consistent and repeatable results. A big 5 test is about as reliable a personality test as you will ever take.

The big 5 is an extremely data-driven system. Tests are very carefully constructed to ask you questions that will measure all the relevant facets for a trait and then balance out all your scores into a total. If you are taking a well designed big 5 test that asks 100+ questions then you can expect a result that will be very similar to any other well designed big 5 test of a similar length. You don't need to agonise for months and months over whether some error has been made and whether your real big 5 scores are actually completely different. If you take several tests and get the same results over and over then those results should be regarded as reliable. While it may seem tempting to assume that a big 5 "expert" can analyse you more accurately than a test, the truth is that big 5 theory is all about number crunching. Calculating big 5 scores means carefully assigning accurate numbers to many different aspects of your personality and then summing those numbers. This is what a test does. Big 5 tests should be considered as reliable as a 1 on 1 analysis, if not more so.

3. Populations do not Show Bi-Modal Trait Distributions

A central assertion of MBTI and Enneagram theory is that there are a set number of types and that everyone can be comfortably slotted into one of these categories. Although there are 32 SLOAN types on PDB, big 5 theory makes no such assertion. The big 5 is a data based system and the data on the distribution of traits tends to suggest the opposite.

There are 5 traits. If the world were divided into people who belong to 1 of 2 distinct categories for each of these 5 traits then there certainly would be 32 distinct types of person. In such a world, if we were to send out tests to a population the results we received would show a bi-modal distribution. Bi-modal as in 2 modes, e.g. Extraverts and Introverts. In this world a graph showing the distribution of Extraversion might show a big hump in the 0-30% range (introverts), another hump in the 70-100% range (extroverts) and a big dip in the middle (ambiverts). In such a world there are few or no ambiverts and everyone can be tidily categorised as either introvert or extravert.

We do not live in such a world. When researchers send out extraversion tests to a population the results they get are the opposite to this. A big hump in the middle (ambiverts) with steep sides grading into gentler slopes that reach thinly outward to the extremes of the scale (extraverts and introverts). This shape is called a bell curve and you will see this kind of distribution appearing across all sorts of naturally occurring metrics: Height, Weight, I.Q. etc. Most people in our world are ambiverts, a mix of middling scores, people who like company sometimes, who like to be alone sometimes, who have an ambivalent attitude towards being assertive or seeking thrills. Unambiguous Extraverts and Introverts are much less common than people who are just sort of middling. The same is true for all 5 personality traits.

So how is this relevant to people trying to work out their SLOAN type? What it means is that a system that only allows for high and low scores has been provided to a population of people who will generally demonstrate mostly middling scores. If you are an ambivert, how do you expect to ever conclusively work out whether you are "Social" or "Reserved"? Why should you even force yourself to apply this false dichotomy? Does it make sense for a 40 year old, 100 I.Q., 5ft 9in man to agonise over whether he is technically more young or old, smart or dumb, tall or short? Recognise the fact that PDB's SLOAN system forces you to pick a high or low score for traits where you may have a totally middling score. For someone who scores very close to 50% for 1 or more traits (this will apply to the majority of people reading this) there is no easy answer to the question of how you work out which of the 32 types is your "real" type. Rather, it is better to acknowledge that the 32 type system is based on a false model, a false assumption of how personality works. You aren't sure whether you're an RLUEI or SLUEI? The fact that you're even asking the question may suggest that you're neither.

Choosing a big 5 type in a big 5 system that doesn't allow for moderate scores can ultimately be like choosing by coin toss. If your score is exactly 50% for Extraversion then you aren't really either RLUEI or SLUEI. This is where expanded SLOAN codes are useful. It makes more sense to summarise your big 5 type on a 3 or 5 point system than on a 2 point system (see the "Expanded SLOAN Codes" page in the "SLOAN" chapter). For voting on PDB however you have no choice but to pick one of the 32 types. Flip a coin. Or take lots of tests and average out your results and if you finally get 51% or 49% then go with that. Just don't assume that you will ever be accurately summarised by one of the 32 types. The data on personality traits certainly does not suggest that you will.