Satya–Chandra: On Accuracy and Precision

Chandra:
Satya, today my measurement matched the true value exactly. So my experiment is perfect, right?

Satya:
Not so fast, Chandra. One correct answer can be luck. Tell me—would you get the same result again?

Chandra:
Hmm… maybe not. Yesterday it was slightly different.

Satya:
Then you may have accuracy, but not precision.

Chandra:
So accuracy is closeness to truth, and precision is consistency?

Satya:
Exactly.
Accuracy asks, “How close am I to reality?”
Precision asks, “How reliable am I?”

Chandra:
Satya, suppose an examiner evaluates a student’s answer.
The student’s true understanding deserves 6 marks.

Satya:
Good. Now tell me—how does the examiner mark?

Chandra:
In one case, the examiner gives 8, 8, 8, 8 every time.

Satya (raises an eyebrow):
Then the examiner is consistent… but biased.

Chandra:
So the marking is precise, but not accurate?

Satya:
Exactly.
Precision reflects the examiner’s habit.
Accuracy reflects the examiner’s judgement.

Chandra:
What if the examiner gives 6, 6, 6, 6?

Satya (smiles):
Then consistency meets truth.
Both precision and accuracy are achieved.

Chandra:
And if the marks are 8, 4, 9, 3?

Satya:
Then the examiner sometimes hits the truth, sometimes misses it.
Accurate on average, but lacking precision.

Chandra (thinking):
So repetition alone doesn’t guarantee fairness.

Satya:
No.
Without accuracy, precision becomes reliable error.
Without precision, accuracy becomes fortunate coincidence.
And remember—without precision, accuracy cannot be trusted;
without accuracy, precision is meaningless.

Chandra:
That sounds like life advice too.

Satya (laughs):
Physics always is.