Correlation and causation traps on GMAT CR

If city A built bike lanes and later saw fewer car crashes, the argument may claim the lanes caused the drop. A strong test taker asks what else changed: traffic volume, enforcement, weather, reporting rules.

On weaken questions, the kill shot is often a third factor that explains both sides. On strengthen questions, the kill shot closes that door.

Correlation language includes after, following, associated with, linked to, and tends to coincide with. Treat those as alarm bells, not proof.

Example style reasoning: regions that buy more ice cream also report more sunburns. Ice cream causes sunburns? Obviously not. Sunny weather drives both. That is the Third Factor Confound in plain clothes.

Sometimes the conclusion runs the causal story backward. Wealthy downtowns may fund rail projects rather than rail projects creating wealth. If the passage only shows correlation, reverse causation is fair game.

Ask: could the effect produce the supposed cause? If yes, you have a classic weaken angle.

Reverse causation shows up in health and behavior arguments all the time. People who sleep more may earn more because higher earners can afford schedules that allow sleep, not because sleep directly raises salary.

When you strengthen a causal claim, an answer that rules out reverse causation can be correct even if it feels indirect.

Even when a cause seems plausible, the author may skip the mechanism. Training improves scores, therefore the training method works. A rival explanation: students who seek training were already more motivated.

Weaken by offering a different cause that fits the same facts. Strengthen by showing the proposed cause is the best remaining explanation after alternatives fail.

Mechanism answers explain how A leads to B step by step. They are common on strengthen items because they shrink the leap between evidence and conclusion.

Authors compare two groups that differ in more than one way. Company X adopted flex hours and saw retention rise. Company Y did not. Maybe Y also cut bonuses. That is a Biased Comparison trap dressed as causation.

Weaken by pointing to unequal starting conditions. Strengthen by showing the groups were similar before the change or that other variables were held constant.

Sample size and time window matter too. A one month spike after a policy change may reflect seasonal hiring, not the policy itself.

Mark the claimed cause and the claimed effect with a simple arrow in the margin. Then list two alternative causes before you read choices. That thirty second habit prevents trap gravity.

Underline words that pretend certainty: proves, shows, demonstrates, clearly. The GMAT rarely gives you clean proof. Answers that mirror that overconfidence are often wrong on weaken stems.

If the stem asks what would most strengthen the causal claim, look for answers that eliminate a major rival or show dose response style logic, not just more correlation.

Batch causation questions by type for a week. Your brain starts flagging correlation language automatically. That recognition speed is what the GMAT rewards.

After each set, sort misses into third factor, reverse causation, or rival explanation. One bucket will dominate. That bucket becomes next week’s focus.

MBA Jump tags these moves so you can revisit the Third Factor Confound and Rival Explanation patterns until they feel automatic. Pair a short timed set with redrill on the tag that still feels slow.