LSAT Logical Flaw Trainer
What is a logical flaw on the LSAT?
A logical (structural) flaw breaks the argument's machinery itself: confusing a necessary condition with a sufficient one, forcing a false choice between two options when more exist, or assuming the very conclusion the argument set out to prove. Every fact can be true and the conclusion still doesn't follow.
What is JBDM?
JBDM — "Just Because Doesn't Mean" — is the Burton Method's foundational framework for attacking LSAT arguments. The formula: "Just because [premise] doesn't mean [conclusion]. Maybe..." You identify the evidence, identify the claim, say the sentence out loud, then generate "maybes" — alternative explanations that expose the gap between them. Once you can articulate that gap, weaken, flaw, strengthen, and assumption questions all become the same job with a different last step.
- Find the parts
- Fill the template
- Attack
Which statement is the conclusion — the claim being sold to you? Tap it (or press its number).
The JBDM template
How this works
Every argument in this trainer is an original Burton Method exercise, pulled from the same drill bank used inside the course — weaken, flaw, strengthen, and assumption sets, each tagged with its flaw pattern. None of it is real LSAT content: LSAC doesn't license PrepTest questions for free public tools, and the method doesn't need them to be trained.
The three-step loop mirrors how the course teaches the move: find the structure, say the JBDM sentence, then generate maybes before seeing any answers. That last part is deliberate — producing an attack yourself, then comparing against a model answer, is retrieval practice plus the generation effect (Roediger & Karpicke, 2006), which builds durable skill in a way that recognizing correct answer choices never does. The model maybes follow Sammy's snowballing doctrine: start bold, get reasonable, and cover every party the argument mentions.
Frequently asked questions
What is JBDM on the LSAT?
JBDM — Just Because Doesn't Mean — is the Burton Method's foundational framework for attacking Logical Reasoning arguments. You identify the premise (the evidence) and the conclusion (the claim), then say: 'Just because [premise] doesn't mean [conclusion]. Maybe...' The maybes you generate expose the gap between evidence and claim, and they become your predictions for the answer choices.
Why train weakening before other question types?
Because in the Burton Method, weaken is the foundation everything else builds on: flaw questions are 'weaken, then describe the weakness,' strengthen is 'weaken, then reverse it to the extreme,' and necessary assumption is 'weaken, then negate it.' Master the attack once and most argumentative LR question types become the same move with a different final step. That's why this trainer drills the attack itself instead of one question type.
What are 'maybes' in LSAT prep?
Maybes are alternative explanations that show why the premise doesn't guarantee the conclusion. You generate them by snowballing: start silly or extreme to get momentum, then get progressively more reasonable. Quantity matters — generate several before looking at answer choices, because the correct answer usually matches one of your maybes or falls under the same umbrella.
How is this different from drilling practice questions?
Answering multiple-choice questions trains recognition — picking the right option from five. This trainer makes you produce the attack yourself before anything is revealed, which is a harder and more transferable skill. Research on the testing and generation effects (Roediger & Karpicke, 2006) shows that generating an answer builds far stronger retention than reviewing one. The answer choices come later; the move comes first.
Will JBDM work on real LSAT questions?
Yes — real Logical Reasoning questions test exactly what JBDM attacks: the support relationship between premise and conclusion. The arguments here are original Burton Method exercises (LSAC doesn't license real questions for free public tools), but the move is identical on test day: find the conclusion, say the JBDM sentence, generate maybes, then match them to the answer choices.
How many reps until JBDM is automatic?
There's no magic number, but the goal is a reflex: you should be saying 'just because... doesn't mean...' on every argument you read without deciding to. Most students feel it click within days of consistent reps and stop thinking about it after a few weeks. Short daily sessions beat marathon ones — ten minutes a day compounds fast.
Is my answer graded?
No — and that's by design. You compare your maybes against Sammy's model maybes and judge yourself honestly: got it, partly, or missed. The comparison is the rep. Nothing is stored, there's no login, and no AI is judging you.
Keep going
That was one rep. The course is 104 lessons of this.
JBDM is lesson one of the Burton Method — Sammy's full system covers snowballing, umbrellas, all parties, and the Two-Runthrough across every LSAT section, with drills like this on every concept.
Try a full free lesson