Speed feedback signs installed; speeding-related fatalities reduced next year. Without other information, this would be an example of:

• A. Causation
• B. Correlation
• C. Experimental effect
• D. Trend

Answer: (B)

Two events happening together suggests a relationship, but it doesn’t prove one caused the other. Seeing fewer speeding-related fatalities after speed feedback signs are installed shows a relationship between the intervention and the outcome, but without additional information we can’t claim the signs caused the drop. Other factors could be at play, such as changes in enforcement, traffic patterns, weather, or improvements in medical response, or simply random variation.

An experimental effect would require a controlled study with random assignment and a comparison group, which isn’t provided here. A trend implies a consistent pattern over many time points, not just one year after an intervention. Causation would mean the signs directly caused the reduction, which we can’t establish from this single observation.

So the best description is correlation: a relationship between the installation and the decrease, without asserting direct causality.