Which of the following is a reliable signal to verify numerical data?

• A. Rely on memory
• B. Cross-check against the original source
• C. Use future projections
• D. Assume based on surrounding numbers

Answer: (B)

Cross-checking against the original source provides the authoritative reference for numerical data. The original document contains the exact values, units, dates, and any notes or corrections that accompany the figure, so it’s the most reliable way to confirm accuracy. This practice catches simple mistakes like transcription errors, misread digits, or unintended rounding that can occur when numbers are copied from summaries or secondary sources. It also ensures the context matches—such as the time period, currency, or scope—so you’re verifying the right data for the right question. Memory is fallible, future projections are estimates, and relying on surrounding numbers doesn’t verify accuracy. By directly comparing to the source, you ground verification in the one place that defines the data’s authority.