A logic game is a puzzle that tests your ability to make logical inferences. Each LSAT analytical reasoning section is made up of four logic games. Some games are harder than others, and there are numerous different types of logic games that you could encounter of the LSAT. However, all LSAT logic games have the same three main components: the scenario, the rules, and the questions.
Logic game scenarios lay the groundwork of the puzzle you are going to solve. The scenario also tells you what variables you will work with in the game. A scenario might look something like this:
Ann, Bethany, Charlie, Ellen, Gertrude, and Juan occupy 6 spots in a line to purchase tickets for a musical. Each person occupies a spot in line, and no person occupies more than one spot. There are only six spots in the line.
You now know what your logic game variables are (Ann, Bethany, Charlie, Ellen, Gertrude, and Juan) and that the variables are arranged in a line. Variables are also called “game pieces.” In the game scenario above, you will likely be asked to determine which game pieces could be in various spots in line. But in order to do that, you will need some rules to follow.
In logic games, the rules are your friends. The rules make it possible for you to answer the questions below, and the more rules you have to work with, the more inferences you can typically make in advance (more on this later). The rules look something like this:
The following conditions apply: Charlie is standing in front of Gertrude. Charlie is not first in line. Gertrude stands directly behind Juan. Ellen is not last in line.
From the rules, you can draw inferences. Logic games inferences are hidden rules that must be true. You are never directly told an inference; you must find inferences by thinking logically. For instance, from the rules given above you can determine the following:
1. Charlie is standing in front of Gertrude. (First rule)
2. Gertrude stands directly behind Juan. (Third rule)
3. Charlie must be standing in front of both Juan and Gertrude. (Inference)
The first two statements are rules. The third is an inference that you can know by thinking about the first two rules. If Charlie is somewhere before Gertrude in line (C – G) and Gertrude is directly behind Juan (JG), then Charlie must be standing in front of Juan (C – JG). Inferences like this one are useful when you approach the logic games questions.
A logic game question might look something like this:
If Charlie is fourth in line, then which of the following must be false? A. Juan is fifth in line. B. Ellen is first in line. C. Bethany is second in line. D. Gertrude is third in line. E. Gertrude is behind Ellen.
The question requires you to not only look at the rules but to make an inference from the rules. In this case, the inference is the one we just saw above: “Charlie must be standing in front of both Juan and Gertrude.” So if Charlie is fourth in line (out of only 6 spots), the fifth and sixth spots must be taken up by Juan and Gertrude respectively. Answer D then must be false, and is therefore the correct answer.
When working through a logic game, you always begin with the scenario. You then move to the rules, where you make inferences. Finally, you answer the questions.
How to Approach the LSAT Logic Games
Each logic game is different, but your general approach to each game should be the same. Work through each of the following steps calmly and methodically.
Get a Sense of the Game
The first step with any logic game is to read the scenario and skim the rules. As you do this, you should be attempting to answer the following questions:
- What kind of logic game is this?
- What are my variables?
- How should I diagram the game?
Make a habit of reading through the scenario carefully. As you do, identify your variables. Usually they will appear in a list (Gabriel, Henry, Jeremy, Katherine, Laura, and Nancy are on a business trip…).
Write Down the Variables
If possible, use one letter for each variable. And try not to use the same letter twice. Write each variable down in small but legible handwriting at the bottom of the page. The bottom of the page is where your entire logic game set-up will be drawn.
Draw a Basic Diagram
The next step is to draw the basics of your diagram. What kind of diagram you draw will depend on the logic game type. The variables and diagram for a sequencing game might look something like this:
Write Your Rules in Logical Notation
Go through each rule one-by-one, and write each one down in logical notation. This step may seem silly to you, but with practice you will be able to read logical notation much faster than you will be able to read a rule written in English words. Plus writing the rules in logical notation makes it harder for the LSAT to trick you with weird wording.
You should also illustrate the rules on the game board itself whenever possible. Illustrating the rules serves two purposes:
- It helps you understand the impact that rule has on the game.
- It makes it easier for you to see the rule later when answering questions.
Make Inferences as You Write the Rules
As you read through the rules and write them down, make inferences. You makes inferences by either considering how rules can be combined or by considering how the game creates limitations. If your inference is valid, then it matters just as much as the rules given to you by the game. So make as many inferences as you can. Every inference you draw makes the game easier.
Circle the Wildcard Variables
After you go through each rule and inference, look for variables that have no rules attached to them. These are your wildcards. (also called floaters). Circle them; quickly identifying your wildcards will be useful later.
If Necessary, Quickly Rewrite your Rules or Redraw Your Diagram
You need to be able to reference your rules and main diagram quickly. So if you made a mess while writing your rules, inferences, or diagram, then it is time quickly (but neatly!) redraw your set-up. The key here is easy readability; nothing can be confusing.
Tackle the Questions
At this point, it’s time to go through the questions. That hard work is done now. If you draw your set-up correctly, then most of the questions will be a breeze.
Here’s an important tip to keep in mind: Once you tackle the questions, never touch your main set-up. Students are frequently tempted to write on the main set-up in order to solve individual questions, but this is a bad strategy. For each question, draw a small diagram next to the question. Use that small diagram to work on the question. This will give you two big advantages:
- Drawing new diagrams is actually faster than erasing old work.
- Drawing new diagrams allows you to keep your old work, which can be useful later.
Because of benefit number two, never erase your work unless you make an error. This will make more sense later, but for now just remember that you do not erase your diagrams unless you make a mistake.