Types / Causal Chain

Average Questions Per Test0.4
Predicted Questions on Modern Test1.8
Causal chain rules are the rarest of the assignment rules, but they almost always travel in packs that take over a game's dynamics. Like tree rules, they usually can be combined to diagram complex interactions between actors that are not immediately obvious if you consider each rule individually. Causal chain assignment games are exclusively about sorting actors into in/out groups or subgroups, and take four different basic forms:

  1. "If x happens, y happens"
  2. "If x happens, y does NOT happen"
  3. "If x does NOT happen, y happens"
  4. "If x does NOT happen, y does NOT happen"
Before you learn how to deal with causal chains, these rare games can seem insurmountably hard, or at least impossible to do within time. This is mainly due to examinees having a terrible time with the contrapositive of the above statements. Don't worry about it if that term scares you: you don't need to learn all of its intricacies, only how to apply the concept where it's necessary.

However, once you know how to recognize, diagram, and apply the diagram, causal chain games are ridiculously easy. These immediate turnaround situations are rare on the LSAT, so enjoy the few points you're about to add!

The key to diagramming causal chains is to clearly differentiate the logical relationship from the trigger and its effect. In the samples above, the trigger is about "x" and the effect is about "y." In the wild, causal chain rules may not be as cleanly stated and you'll have to translate them into diagrammable concepts.

The Sample Questions with Explanations has one game and one question with causal chain rules. While reading this first paragraph, try to find the language in the sentences that tells you actors who are "in" or "out" based on a cause, or things that cause other actors to be "in" or "out." Hint: it's not the highlighted language, which is an important finite slots rule that will help us draw our workbench.

Which rules are stated as causal chains?

Rules 1-3 are all causal chains, and--uncharacteristically--only overlap on a single actor: S. We'll add in some fake rules in a bit to make this more like modern causal chain games, but for now, let's worry about how to diagram and read these pieces. Starting with the basic workbench you should be able to draw from your understanding of finite slots, I'll draw arrows from the trigger(s) of each rule to the effect(s) of each rule. The arrowhead is incredibly important, as it will help us deduce information in the

The basic workbench is in black, while the colored text is a visual diagram of rules 1-3.

Now let's test what you can deduce based on a given piece of information. This is tricky, and right now we're only going to test one thing: if everything at the start of an arrow matches the trigger, then you can apply that trigger to everything after it. Positive matches at the end of an arrow, however, cannot be applied back to the trigger, as the trigger could be there or not.

  1. You know that G is being reduced ("is in"). What else do you know?
  2. You know that W is being reduced. What else do you know?
  3. You know that L is NOT being reduced. What else do you know?
  4. You know that N is being reduced. What else do you know?
The answer to the first three of these is: nothing! For number four, we can deduce two things.

  • G doesn't trigger anything by itself. If you had both G and S, then you'd also be able to deduce that W is in.
  • Knowing that W is in tells us nothing about any other actor, not even G and S. The arrowheads are crucial for this: you can only apply positive matches along the chain, and can't read positive matches backwards. That is, even if you have W, which matches what is at the end of an arrow, you can't tell anything about what came before it.  G and S could be in or not.
    • Similarly, if you DON'T have L, which matches what is at the end of an arrow in the third rule, you don't know anything about P, which could be in or not.
  • Even though L is not in, that "matches" what the end of rule 3 states. Thus, positive matches at the end of an arrow don't tell us anything about the trigger.
  • Last, if we know that N is in, that matches on to all of the trigger in the second rule. That means we know BOTH parts of the trigger's effects: R is out and S is not.
Note that whether the rule is about being "in" or "out" doesn't, by itself, affect whether or not we can deduce anything; what matters is whether or not the piece of information we have matches all of a trigger.

Now, let's practice reading negative matches, which is technically applying the contrapositive of the rules. Again, don't get scared, this is super easy. If we know that the end of a causal chain is false, i.e., it does not match, then we know that everything that comes before it in the chain is also false. That is, you can apply positive matches to triggers forward along the arrows, and you can apply negative matches to effects backwards along the arrows. So, what else do you know, given:

  1. You know that R is out.
  2. You know that S is in.
  3. You know that L is in.
  4. You know that W is not in.
You don't know anything in the first case, but can deduce some things in 2 through 4.
  • R being out is a positive match for one of the effects from the N trigger, and thus we can't read positive match effect backwards.
  • Oppositely, S being in is a negative match for one part of the effect from the N trigger. Thus, we can negate any causes leading to that trigger: the negation of "N being in" is that "N must be out." Thus, we know that N cannot be in.
    • Bonus and review for reading information forward along chains: if N is not in, do we know anything about R? Does "no N" match the trigger? No, and thus we know nothing about R.
    • This emphasizes that the different branches of a casual chain do not interact with each other if the trigger is negated.
  • If L is in, that is a negative match to the third rule's effect. Thus, we can also negate any triggers leading to that effect, and we know that P cannot be in.
  • I W is not in, that is a negative match to the first rule's effect. We can negate both parts of the trigger that lead to W, and we know that both G and S cannot be in.
Now, let's change up one of the causal chain rules so that we can practice more complex relationships with branching causalities: the text of rule two for the following examples reads:

If N is reduced, S is also reduced but R is not reduced.
When we draw in the diagram for this rule instead of the real rule 2, what we have is an overlap for a trigger in the first rule (S being in) and an effect from rule to (S also being in). Thus, we can draw the two rules so they overlap, and combine the causal "trees" into a single diagram.

Note that Rule 3 is still off in its own causal chain.

Alright! Before we practice reading this diagram, let's clarify some of the rules for interpreting multiple arrows and branching chains.

First, reading positive matches forward starts only at the trigger that is matched and continues as long as the chain goes.

Second, reading negative matches backwards starts only at the trigger that is matched and continues only along direct "arrow" paths.

Third, combining these first two clarifications to complex diagrams: the branches of different effects do not apply unless their trigger is matched. So, what else do you know, given:

  1. W is not in.
  2. R is in.
  3. S is in.
  4. S is not in.
  5. N is in.

  • If W is not in, that is a negative match to the effect of Rule 1. Thus, we know that both G and S are also not in (reading negatively backwards). If S is not in, then that is a negative match to one of the effects of Rule 2. Thus, we also know that N is not in.
    • Bonus review: if N is not in, do we know anything about R? No, we don't, because we don't have a positive match in Rule 2 and thus we don't activate the trigger.
  • If R is in, that's a negative match for one of the effects of Rule 2. Thus, we know that N is not in (reading negatively backwards).
  • If S is in, that's a positive match to one of two triggers in Rule 1 (so we can't read forward without also having G) and one of the effects in Rule 2 (so we can't read positive matches backwards). Thus, we don't know anything else!
  •  If S is not in, then that's a negative match to one of the triggers in Rule 1 (so we can't read the trigger forward) and one of the effects in Rule 2. Thus, we can read the negative match backwards--only in Rule 2--and know that N is also not it.
  • If N is in, then that's a negative match to the only trigger in Rule 2. We can read it forward to both effects: S is in and R is out.
    • Bonus: If S is in, does that mean that W is also in? Only if G is also in, because then both triggers from Rule 1 are positively matched. 
And now you've got a handle on the last assignment rule type you'll run in to. Grouping rules await.
GroupTestQ #SectionAnswerYour AnswerDistractorDifficulty
PT 65 12-16 (3/10)PT 65122BMedium
PT 65 12-16 (3/10)PT 65132DBHard
PT 65 12-16 (3/10)PT 65142EMedium
PT 65 12-16 (3/10)PT 65152DCVery Hard
PT 65 12-16 (3/10)PT 65162AMedium
PT 64 7-12 (1/6)PT 6472BEasy
PT 64 7-12 (1/6)PT 6482ADMedium
PT 64 7-12 (1/6)PT 6492EEasy
PT 64 7-12 (1/6)PT 64102AHard
PT 64 7-12 (1/6)PT 64112CAMedium
PT 64 7-12 (1/6)PT 64122DMedium
PT 59 11-16 (1/9)PT 59111DMedium
PT 59 11-16 (1/9)PT 59121EMedium
PT 59 11-16 (1/9)PT 59131CAHard
PT 59 11-16 (1/9)PT 59141AHard
PT 59 11-16 (1/9)PT 59151DMedium
PT 59 11-16 (1/9)PT 59161ACHard
PT 58 7-12 (5/8)PT 5873CEasy
PT 58 7-12 (5/8)PT 5883BAMedium
PT 58 7-12 (5/8)PT 5893CEasy
PT 58 7-12 (5/8)PT 58103BVery Easy
PT 58 7-12 (5/8)PT 58113AMedium
PT 58 7-12 (5/8)PT 58123BAHard
PT 50 6-11 (2/11)PT 5063EEasy
PT 50 6-11 (2/11)PT 5073DEasy
PT 50 6-11 (2/11)PT 5083BEasy
PT 50 6-11 (2/11)PT 5093AVery Easy
PT 50 6-11 (2/11)PT 50103EMedium
PT 50 6-11 (2/11)PT 50113BEHard
PT 49 1-7 (1/8)PT 4911EEasy
PT 49 1-7 (1/8)PT 4921DEasy
PT 49 1-7 (1/8)PT 4931ADMedium
PT 49 1-7 (1/8)PT 4941BEasy
PT 49 1-7 (1/8)PT 4951DMedium
PT 49 1-7 (1/8)PT 4961EEasy
PT 49 1-7 (1/8)PT 4971DBHard
PT 49 13-17 (4/6)PT 49131AVery Easy
PT 49 13-17 (4/6)PT 49141CMedium
PT 49 13-17 (4/6)PT 49151AEasy
PT 49 13-17 (4/6)PT 49161DEasy
PT 49 13-17 (4/6)PT 49171EMedium
PT 47 6-11 (1/6)PT 4764BVery Easy
PT 47 6-11 (1/6)PT 4774AMedium
PT 47 6-11 (1/6)PT 4784BMedium
PT 47 6-11 (1/6)PT 4794CMedium
PT 47 6-11 (1/6)PT 47104CBMedium
PT 47 6-11 (1/6)PT 47114CEasy
PT 45 13-17 (4/7)PT 45133BMedium
PT 45 13-17 (4/7)PT 45143EBMedium
PT 45 13-17 (4/7)PT 45153DBMedium
PT 45 13-17 (4/7)PT 45163BEasy
PT 45 13-17 (4/7)PT 45173AEasy
PT 39 19-23 (6/10)PT 39191CVery Easy
PT 39 19-23 (6/10)PT 39201AVery Easy
PT 39 19-23 (6/10)PT 39211AEasy
PT 39 19-23 (6/10)PT 39221CVery Easy
PT 39 19-23 (6/10)PT 39231BEasy
PT 36 1-6 (4/6)PT 3614BEasy
PT 36 1-6 (4/6)PT 3624DEasy
PT 36 1-6 (4/6)PT 3634EMedium
PT 36 1-6 (4/6)PT 3644CMedium
PT 36 1-6 (4/6)PT 3654EMedium
PT 36 1-6 (4/6)PT 3664CAMedium
PT 34 19-24 (5/7)PT 34194BCVery Hard
PT 34 19-24 (5/7)PT 34204AMedium
PT 34 19-24 (5/7)PT 34214CMedium
PT 34 19-24 (5/7)PT 34224AHard
PT 34 19-24 (5/7)PT 34234EAHard
PT 34 19-24 (5/7)PT 34244BMedium
PT 33 6-12 (4/5)PT 3364DMedium
PT 33 6-12 (4/5)PT 3374EEasy
PT 33 6-12 (4/5)PT 3384DEasy
PT 33 6-12 (4/5)PT 3394CEasy
PT 33 6-12 (4/5)PT 33104AMedium
PT 33 6-12 (4/5)PT 33114AEasy
PT 33 6-12 (4/5)PT 33124BEasy
PT 23 6-11 (2/6)PT 2361CVery Easy
PT 23 6-11 (2/6)PT 2371EEasy
PT 23 6-11 (2/6)PT 2381EMedium
PT 23 6-11 (2/6)PT 2391EEasy
PT 23 6-11 (2/6)PT 23101BMedium
PT 23 6-11 (2/6)PT 23111BMedium
PT 21 7-11 (2/6)PT 2171DEasy
PT 21 7-11 (2/6)PT 2181AVery Easy
PT 21 7-11 (2/6)PT 2191AMedium
PT 21 7-11 (2/6)PT 21101BMedium
PT 21 7-11 (2/6)PT 21111AVery Easy
PT 20 6-12 (3/6)PT 2063AVery Easy
PT 20 6-12 (3/6)PT 2073EEasy
PT 20 6-12 (3/6)PT 2083BEasy
PT 20 6-12 (3/6)PT 2093AEasy
PT 20 6-12 (3/6)PT 20103ABHard
PT 20 6-12 (3/6)PT 20113CEHard
PT 20 6-12 (3/6)PT 20123EAHard