Passage Summary: Researchers asked office workers how much they used computer screens and how many headaches they had; because the heavy screen users had more headaches, the researchers decided the screens were the culprit.

Conclusion: Using video display terminals (VDTs) is the direct cause of headaches in office workers.

Reasoning: A survey showed a correlation where workers who reported higher VDT usage also reported a higher frequency of headaches compared to their peers.

Analysis: The researchers are jumping from correlation to causation, which is a classic trap on the LSAT. To weaken this, we need to find an alternative explanation for the headaches or suggest the causal direction is reversed. Perhaps people who already have headaches are more likely to notice or over-report their screen time, or maybe a third factor, like poor office lighting, causes both the headaches and the need for more screen time. Look for an answer that breaks the link between VDT use specifically and the onset of pain.