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5 Tiny Mistakes in LSAT Games that can Cost Big Points:

  1. Misunderstanding Conditional rules:

    Most people who have already begun studying for the LSAT have probably already encountered this mistake. However, in case you haven't started studying yet you need to know that the rule “If F is in 3, then G is in 5” does NOT mean that putting G in 5 will force F to be placed in spot 3. Placing F in 3 forces G, but placing G in 5 does not force F. This mistake is easily avoided by remembering that the word “if” introduces the forcing condition (commonly referred to as the “sufficient condition”).

    “If F is in 3, then G is in 5”


    Watch Out! Sometimes the word “if” appears in the middle of the sentence instead of at the beginning. An example is this wonderful rule from a June 2001 Logic Game: “Kudrow is at Randsborough if Juarez is at Souderton.” This rule means that if Juarez is at Souderton, then Kudrow must be in Randsborough, but if Kudrow is in Randsborough, Juarez could be anywhere.

    Circling “if”, “only if”, and “unless” can prevent major mistakesHow to avoid this problem: Circle the key word(s) in the rule, like “if”, “only if”, and “unless”. This will help you notice when “if” appears in the middle.

  2. Diagramming Before/After Rules with a dash:

    A dash can look a lot like an underscore. Consider the following two rules:
    “A must arrive some time before B” and “C must come before D and there must be exactly one space between C and D”. If you symbolize the first as A – B and the second as C _ D, then test day jitters or messy handwriting can lead you to mix the two up on test day.

    On test day
    A – B can look a lot like C _ D!
    How to avoid this problem: Use a "lollipop" symbol for before and after.
    (Other symbols we do not recommend:
    Greater than/Less than -- in vertical rules, the sign can be confused with the letter V.
    Dots -- These take longer to draw and can sometimes rip through flimsy test booklets.
    Arrows -- these must be reserved for conditional rules.)

  3. Mixing Up Two Days Before/After with Two Days Between:

    When a rule says “A is before B and there are two days between them.” this should be diagrammed as you would expect: A _ _ B. However, when a rule says “A must arrive exactly two days before B” then this means A _ B. (If B arrives on Thursday, then A would arrive two days before, on Tuesday. There would be one day between them.)

    How to avoid this problem: A simple rule-of-thumb is "between" = the number stated goes between. "days before/after" = one less than the number stated goes between.
    So, "G arrives exactly three days after H" will be diagrammed with one less than three (two) spaces in between.
    H _ _ G

  4. Mixing Up “Higher-Numbered” and “Lower-Numbered”:

    Remember: the Lower number should be on the Left! This is a simple one that most people never think they would mix up, until they do. This small example appeared in a logic game from Test #16, “J must be assigned to a stall numbered one higher than K's stall.” When my students would do this game in class, I would stop them halfway through and announce that the rule should be symbolized as “KJ” rather than “JK”. At least a third of them would moan and begin to erase. (If you’re finding this confusing, remember that spaces are numbered 1 2 3 4... 4 is numbered one higher than 3, and is to the right of 3.)

    How to avoid this problem:Remember to double-check rules like these when solving games. I use this simple mnemonic device: Lower-number should be on the Left.

  5. Testing whether something Must be True by trying it:

    If you need to test an answer choice for a question that asks what must be true, remember that you need to try to DISPROVE the choice, that is, to see whether the choice could be false. If you simply test the answer as it's stated, then you are discovering that the condition COULD be true, but this does not mean that it MUST be true.

    A quick example: C, D, and E are three letters that must be placed into three different slots, numbered one through three in a straight line from left to right. C and D cannot be in consecutively numbered slots.

    Which of the following must be true?
    A) C occupies slot 1.
    B) E occupies slot 2.

    Suppose you just weren’t sure which of these had to be true and you wanted to test the choices. You would make a huge mistake if you began by placing C in slot 1. Certainly C could go in slot 1, but this doesn’t mean that it must go in slot 1, which is what the question asks.

    Instead, you would test choice A by attempting to place C in a slot other than slot 1. Slot 2 clearly won’t work, because this would force C to be consecutive with D, which is prohibited by the rule in the game. However, C can occupy slot 3, with D in slot 1 and E in slot 2.
    (C can occupy slot 1 or slot 3)

    E, however, cannot occupy any slot other than slot 2. Placing E in slot 1 or 3 would leave two consecutive blank spaces for C and D, which cannot be consecutive.
    (Placing E in either slot 1 or slot 3 will leave no place for C and D.)

    Written by: Bernadette Chimner Copyrighted by Griffon Prep, 2007.
    Bernadette "Bernie" Chimner managed to eliminate the tiny mistakes from her own LSAT preparation, and successfully answered every question on the June 2005 LSAT correctly, scoring a 180. She has been teaching and tutoring LSAT professionally since 1999 and currently works for Griffon Prep, a company dedicated to rigorous coursework, small classes, and extraordinary personal attention.

    Other LSAT articles you may find useful:

    A Few Ideas for Dealing with Test Anxiety on the LSAT
    A Sample Logic Game

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