Hi Dave, the other day I had a slight stressful moment that made me change my registration from September to December. Is this a disadvantage with the application process for Fall 2018 as December scores are released after the new year?
This is a very good question, and one that we hear often. The short answer is that it's not a problem to take the later test, and thus December will be just fine. But in making that decision, it's helpful to keep the following rule in mind: Take the LSAT that will produce the highest score for you. Let's talk about that first, and then come back to the idea of whether taking December is too late in the application stream.
Conventional wisdom dictates that you should submit your completed application as early as possible because law schools use a rolling admissions process, which means that schools consider applicants in batches as the applications arrive. When an application comes in at the beginning of the application period (in the fall of each year), there are the fewest number of competing applications completed and the greatest number of available spaces in the class. That situation then reverses over time, and as students are accepted, there are fewer available spaces but of course more total applicants since the applications keep rolling in. So, the benefit of applying early is established. But, it's just one factor in admissions decisions, and by comparison, your LSAT score plays a much larger role (see Why Is My LSAT Score So Important In The Law School Admissions Process?). At most school, your LSAT score is the single most important factor in your application, and so you want to do everything possible to submit the highest score you can achieve. Thus, when compared to how early you apply, a higher score takes precedence (even that score is just 1 or 2 points higher!). We did a statistical analysis of applicants, and results bore this out—see Does submitting an early law school application improve your chances? for the full analysis. The bottom line is that if taking the December LSAT positions you to score just a bit better, then it's a superior choice to September.
So, the above should make you feel better from a score standpoint, but let's also look at how applying December places you in the applicant group as whole. LSAC released applicant numbers a while back, and I made an analysis of when students applied based on that information—see Hoping to apply to law school early? What actually is early? for the full discussion. If your application is complete by about January 10th or so, you will still be in what's called the First Group, which is the first 40% of applicants. Thus, regardless of score considerations, while September does allow you to apply earlier, December still allows you to be in the first half of applicants and that's pretty reasonable.
Please do not hesitate to let me know if you have any questions. Thanks!