This posting is an expansion of a lightning talk that I gave at Agile 2009. Many thanks to Arlo Belshee and James Shore for providing the platform. Many thanks also to the programmers and testers at the session for the volume of support that the talk and the idea received. Special thanks to Joe (J.B.) Rainsberger. Spread the meme!

There is confusion in the software development business over a distinction between testing and checking. I will now attempt to make the distinction clearer.