Question 9.12: Which of the three sources of distortion in the transfer of ...

Although the significance of each potential source of distortion differs depending on the particular situation, the following three are usually the most important:

(a) Malicious external manipulation of the object or sample.
(b) The type of information required.
(c) A poor knowledge of the required information and its features.

The latter two sometimes exchange their place in the significance ranking.