Systematic bias is a bias resulting from the system, leading on average to
systematic errors, in contrast to random errors, which on average cancel
each other out.
An example of systematic bias would be a thermometer that always reads three degrees colder than the actual temperature because of an incorrect initial calibration or labelling, whereas one that gave random values within five degrees either side of the actual temperature would be considered a random error.
Once detected and quantified, it may be easy to compensate for a
systematic bias. In the example just given, one knows that the
thermometer always reads three degrees below the correct value. Thus,
one can simply make a systematic correction by adding three degrees to
all readings. In other cases, while a systematic bias is suspected or even
detected, no simple correction may be possible because it is impossible to
quantify the error. Random errors can in some cases be reduced by
repeating the experiment several times and considering an average
result; in other cases repetition is not possible.
The existence and causes of systematic bias may be difficult to detect without an independent source of information; the phenomenon of scattered readings resulting from random error calls more attention to itself from repeated estimates of the same quantity than the mutually consistent incorrect results of a biased system.
However, systematic bias can additionally sometimes be used to imply
planned human agency. Systematic bias therefore can also mean that the
system produces bias as a consequence of consistent, deliberate and
planned human interference.
Disinformation techniques may also be found in commerce and
government, used by one group to try to undermine the position of a
competitor. It in fact is the act of deception and blatant false statements
to convince someone of an untruth
Unlike traditional propaganda and Big Lie techniques designed to engage
emotional support, disinformation is designed to manipulate the audience
at the rational level by either discrediting conflicting information or
supporting false conclusions.
Another technique of concealing facts, or censorship is also used if the
group can affect such control. When channels of information cannot be
completely closed, they can be rendered useless by filling them with
disinformation, effectively lowering their signal-to-noise ratio.