Science · Level 5 · 212 words

Sealed Until the End

Original passage © Studio AM, written for Fluency.

Plot measurements of a physical constant by year, and the points can tell an awkward story. The classic case is the charge of the electron: Millikan's celebrated value was slightly low, yet later measurements did not jump to the true value. They crept toward it over twenty years, because a result that strayed far from the famous number was rechecked until it behaved, while one that agreed was published as it stood.

No one was faking data. The bias worked through a smaller door: an analysis involves hundreds of judgment calls (which runs to discard, when to stop hunting for errors), and researchers who know the expected answer stop hunting the moment their number matches it.

Modern collaborations defend against their own expectations with blind analysis. Before anyone looks, a computer adds a secret offset to the quantity being measured, so every intermediate result is deliberately meaningless. The team debates every cut and correction blind to what each choice does to the answer. Only when the whole procedure is frozen in writing is the offset removed, and the number that appears is the number published.

The method concedes something uncomfortable: training does not remove the thumb from the scale. What removes it is making the scale unreadable until the weighing is done.

Comprehension questions

Choose an answer, then check your work. Nothing is saved or sent.

4 questions
1. Which statement best expresses the passage's main idea?

Show answer for question 1

B. Because expectation steers honest judgment calls, physicists now hide the answer from themselves until the analysis is fixed.
The electron story shows how bias works through legitimate choices; blind analysis is the engineered response. The main idea must join the disease to the cure.

2. Why did later measurements of the electron's charge creep toward the true value instead of jumping to it?

Show answer for question 2

D. Results near the famous number escaped the extra error-hunting that distant results received, dragging each new value only partway.
The passage names asymmetric checking: a straying result was rechecked 'until it behaved,' while one that agreed was published as it stood. Gradual instrument improvement is the tempting cause the text never offers.

3. In 'a computer adds a secret offset,' an offset is:

Show answer for question 3

A. an amount added to shift a value away from its true reading
The next clause does the defining: with the offset in place, every intermediate result is 'deliberately meaningless,' so it must be a shift applied to the measured quantity itself.

4. According to the passage, when is the secret offset removed?

Show answer for question 4

C. Only when the whole procedure is frozen in writing
The passage is exact: the offset comes off only when the procedure is frozen in writing, and the number that appears is the one published.

Source: Written for Fluency. Original passage © Studio AM, written for Fluency.