Progressive enhancement as the word ‘enhancement’ suggests means ‘looking forward’ or ‘being enhanced’. It is the practice of building websites for the most commonly used device or browser. More advanced functionality is then built in for more advanced browsers; as when designing for mobile first, progressive enhancement allows functionality to be added for larger screen sizes. It has been “found that designs optimised for mobile devices first adapt easier to wide screens than wide sites cram down to mobile. In the long run, it’s easier to expand than to shrink (Zurb Inc, 2015).”
Graceful degradation is the opposite, as the words suggest ‘looking back’. It is the practice of building websites from a higher level as viewed on the latest/newest browsers or larger screen sizes i.e. desktop. Functionality is added enabling the site to degrade gracefully to work with older browsers or smaller devices i.e. mobiles.
Zurb Inc. (2015) Graceful Degradation [Online] Available From: http://zurb.com/word/graceful-degradation [Accessed On: 18 October 2015]