Effective diagramming techniques is critical to your success on the analytical reasoning section of GAT General / Local GRE or other tests. There are a few people who can look at a logic game and ace it without any diagrams. If you are one of those people, then you do not need this course. For the rest of us, excellent diagramming skills are required. This lesson is meant to introduce you to some diagramming techniques. None of these techniques are set in stone. Every student must use the techniques that work best for them.
Any good diagramming system must be:
§ Fast – you must be able to express ideas in shorthand to save time
§ Neat – messy notations will cost you points
§ Easy to Understand – You must instantly understand what your notations mean
Here we suggest some notation and diagramming techniques. When you have completed this tutorial you can find additional diagramming instruction in our Logic Games explanations.
Entities: One of the first steps in setting up your diagram is write down a letter or number to represent each of your entities. Each game will have a list of entities that will be placed into an order or groups or both. Start by writing down this list of entities. For e.g., you are told that there are 5 different dogs in a race and they are a Labrador, Mixed Breed, Newfoundland, Poodle, and a Schauzer. Record this list of entities as follows:
L M N P S
Notice that we only used one letter for Mixed Breed. There is no sense in confusing yourself with additional letters. Keep it to one letter per entity. Also notice that the entities are given in alphabetical order. This is usually the case on the LSAT. However, they will often leave a letter or two to confuse you. Some students will unwittingly insert that letter by force of habit. For e.g., in this question many students might just add in the letter O because they are used to O following L M N. Make sure your list of entities matches those given.
Now that we have our list of entities we can move on to the diagram itself.
Basic Linear Sequence Game set up:
A Linear Sequence Game will ask you to place a set of entities in order. This could be expressed in a number of ways including: 1st to 6th, First to Last, Monday to Friday, Top to Bottom, Front to Back, etc.
In order to make a place for each entity in your diagram simply put an underline for each space where an entity will go. So if we are told to list five dogs in order from fastest to slowest we can set up our game as follows:
______ ______ ______ ______ ______
We now have 5 spots for our 5 dogs. If you want, you could put F and S at the ends of the diagram to represent that it goes from Fastest to Slowest. This is usually not necessary and can waste time when you are re-drawing your diagram. If you chose to include this extra notation make sure that the F and S do not match any of your entities. For example, if you had a Schnauzer as one of your dog types you would not want to have S for Schauzer and S for slowest. One way you can avoid this is to put the f and s for fast and slow in lower case.
Now that you have your basic diagram for a Linear Sequence game set up we move on to inserting our rules.
Fixed entity: If we are told that an entity is placed in one spot then we can just fill that directly into the diagram. This is the easiest type of rule to include. For example, if we are told that the Schnauzer will be 3rd fastest then we can include it as follows:
S
______ ______ _______ ______ ______
Not in that spot: If we are told that a particular entity does not go in a particular spot we should add that directly to our diagram by putting the entity under that spot and designating that it does not go there. There is a number of ways to designate that the entity does not go there. You can put a slash through it, or put ~ in front of the entity. Find one that works best for you. For example, if we are told the Poodle is not the fastest dog we can include it in our diagram as follows:
S
______ ______ ______ ______ _____
Here /There Pair Notation:
This notation is used when two entities are going to fill two spots but we don’t know which entity is in which spot. For e.g., if K and T must be in spots 2 and 3. We know we either have K in 2 and T in 3 or T in 2 and K in 3.
The way to express this with the Here or There Pair notation is as follows:
K/T T/K
______ ________ ________ _______ _______
What this means is that as soon as we place K or T we know exactly where the other entity must go. If we place K we know where T is and vice versa.
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