Author and entrepreneur Eric Ries stresses continuous deployment - that is, the updating of code and website changes as frequently as every twenty minutes - as a necessary asset to the functioning of a lean startup. He states that all online product development and engineering changes should be implemented slowly and with immediate testing for each small change. Working in small batches allows for the immediate catching of errors, quick team response, reduced implementation of resources, and more control and flexibility over the finished product. And along the way, human intervention also builds up the intelligence and capabilities of the in-house testing and deployment systems. Ries also offers specific applications and engineering functions to make continuous deployment possible.