Redundancy: a double-edged sword

Information theorists call everything that is superfluous in a data set simply 'redundant'. They initially regard these duplications as annoying because they only unnecessarily inflate databases without adding information. Almost every message contains such redundancies, which could be omitted without harming the information content. IT programmers call such an intervention in the database 'deduplication'.

However, redundancy also has positive aspects because it can check itself for errors. Redundancy deviations from each other would then be 'alarm signals' that indicate incomplete or faulty transmission. In information theory, it is therefore always necessary to weigh up the quality of a database (high redundancy) against the quantity of data transmission (with low redundancy).