Key words

Question 1

Accurate

Answer 1

a measure of the closeness of agreement between an individual test result and the true value.

Question 2

Confidence

Answer 2

a qualitative judgement expressing the extent to which a conclusion is justified by the QUALITY of the evidence.

Question 3

Error (of measurement)

(Standard Deviation)

Answer 3

the difference between an individual measurement and the true value (or accepted reference value) of the quality being measured.

Question 4

Precision

(relates to equipment used)

Answer 4

the closeness of agreement between independent measurements obtained under the same conditions. It depends only on the distribution of random errors (ie the spread of measurements) and does not relate to the true value.

Question 5

Repeatability

(Standard Deviation)

Answer 5

the precision obtained when measurement results are produced over a short timescale by one person (or the same group) using the same equipment in the same place.

Question 6

Reproducibility

Answer 6

the precision obtained when measurement results are produced over a wider timescale by different people using equivalent equipment in different (but equivalent places)

Question 7

Validity

Answer 7

can apply to an individual measurement or a whole investigation.
a measurement is valid if it measures what it is supposed to be measuring.
an investigative procedure is valid if it is suitable to answer the question being asked.
validity will be reduced, for example, if no negative control is included in an investigation into the efficacy of a therapeutic drug.