Whether the test is getting more and more "unusual" or "weird" is a question we get on a weekly basis. It's an understandable worry: all of your prep work is based on the fundamental assumption that the skills being tested on the LSAT do not vary from one administration to the next. Rest assured that they do not: every LSAT tests your ability to reason with conditional statements, to infer what must be true or false from a given set of rules, to recognize logical equivalency and reason from analogy, to determine the effect of additional statements on the logical validity of a given argument , to identify the conclusions, fallacies, and assumptions of various arguments, etc. That said, it is absolutely true that in recent years, LSAC has made a concerted effort to test these skills in more unusual and less predictable ways.
As discussed in the LSAT Casino blog post, the emphasis on each concept varies from test to test. This would explain, to an extent, why you may get 18 out of 25 on one LR section, and 23 out of 25 on another. Maybe the second section played to your strengths in causal reasoning, whereas the first section penalized you for not fully understanding the concept of conditionality. We cannot predict which concepts will be favored (or disfavored) on your next LSAT, which is why you should be rock solid on all of them. That said, it is undeniably true that the following general trends in Logical Reasoning have emerged in recent years:
- Causal reasoning has become exceptionally common, particularly in the context of scientific arguments. For someone taking the test in 2016-2017, is absolutely imperative to understand concepts such as correlations, coincidences, and controlled experiments. It is equally important to know how to strengthen and weaken causal arguments, and remember that while many causal arguments are quite weak, that does not necessarily make them invalid or flawed.
- Formal Logic is not nearly as common as it used to be. While you may still come across questions that test your ability to use propositional logic and formally diagram a set of relationships in order to deduce a provable claim, test makers have moved away from this paradigm. For a good reason: it's imminently learnable from perusing a basic textbook on logic.
- Numerical and statistical evidence: arguments that use such evidence have increased in both frequency and difficulty. Test-makers expect you to understand sampling concepts, proportions, averages, variances and percentiles, risk and probability, sensitivity and specificity, etc. Still, only a handful of questions test these concepts, so if you're still struggling to understand what an assumption is, you are better off focusing on that instead.
- Flaw questions have increased in frequency and difficulty as well. It is critical to understand the range of logical fallacies you may come across on a given test.
- Principle questions have also increased in frequency, particularly Strengthen-PR questions. These have also become a bit more unusual in recent years. For instance, it is not uncommon these days to be presented with a stimulus in which (1) a principle is outlined; (2) a situation is described; and (3) the stem asks you to identify an additional piece of information that will justify the applicability of the principle to that situation. While this is not a question we would expect to find on a test from 2001, rest assured that the fundamental skills being tested are all the same.
In Logic Games, curve balls have also become the the new normal. Pattern Games are having a comeback (see June 2014 and December 2015), and from the looks of it there was a highly unusual game involving computer viruses on the September 2016 LSAT. Other oddities, such as sequencing/conditional rules, the Rule Substitution Question, etc. are also catching on. Since the Logic Games section is by far the most learnable part of the test, it is reasonable to expect less predictability, and more "curve balls" as time goes by. You can still take comfort in knowing, however, that at least 3 of your games will fall into the predictable categories of Linear, Grouping, and Combination games.
So, is the LSAT getting weirder? No, as long as you understand that "weird" is the new normal. If you expect to see a few curve balls on your next test, the test won't feel weird at all.