The '''Data processing inequality''' is an [[information theory|information theoretic]] concept which states that the information content of a signal cannot be increased via a local physical operation. This can be expressed concisely as 'post-processing cannot increase information'.<ref name= BeaudryArxiv>{{citecitation |journal=Quantum Information & Computation |volume=12 |issue=5-6 |pages=432-441432–441 |last1=Beaudry |first1=Normand |title=An intuitive proof of the data processing inequality |date=2012 |arxiv=1107.0740}}</ref> As explained by ''Kinney and Atwal'', the DPI means that information is generally lost (never gained) when transmitted through a noisy channel.<ref>{{cite journal|pmid=24550517 | doi=10.1073/pnas.1309933111 | last1=Kinney | last2=Atwal | volume=111 | title=Equitability, mutual information, and the maximal information coefficient. | date=Mar 2014 | journal=Proc Natl Acad Sci U S A | pages=3354–9}}</ref>
