Avoid leaving the impression that you encourage teams to include spike stories any time unknowns exist. Scrum teams often are expected to work with a high level of ambiguity. Adding research stories every time this occurs slows down production and indicates that the teams you have led are unable to break down their user stories properly for their selected sprint length.

A Spike is a story that a team adds to a backlog to represent work necessary to research a story or series of stories that have an unusually high level of risk or unknowns. For example, a project may require a team to work with new technology. They may add a Spike story for one of the developers to build a proof of concept, play with the options available, and determine how to integrate the tool into their environment. The Spike is time-boxed and should make the development of stories further down in the backlog easier to implement.