One of the important point in the Scrum Agile project management approach is the fact that user stories are estimated using a relative size and not the “exact” man/days measure used to size effort by traditional approaches. In his blog post, Ilan Goldstein discusses how to explain the relative estimation concept in Scrum.
In this article, Mitch Lacey discusses the difficulty faced when trying to provide estimates for software development project. The beginning of a software project is the time when you are the least certain about the final scope project, but it is also when you are asked to deliver precise estimates. Agile tries to move from uncertainty to certainty in as quickly as possible.
The first step in creating a useful Agile project plan is the ability to estimate reliably. Mike Cohn discusses how to do this. He explores various approaches to estimating in Scrum including unit-less points and ideal time. The class presents four specific techniques for deriving reliable estimates, including how to use the popular Planning Poker® technique and other techniques that dramatically improve a project’s chances of on-time completion.
Planning Poker is an Agile practice that harnesses the “wisdom of the crowd”. The goal of planning poker is not to derive an exact and accurate estimate that would stand all future scrutiny, but rather, to obtain a group estimate in a fast, cost effective and collaborative way.
Estimating and planning are critical to the success of any software project, also in the case of distributed agile development. Research has acknowledged that conventional agile methods need to be adjusted when applied in distributed contexts. However, we argue that also new tools are needed for enabling effective distributed agile practices. This article presents eConference3P, a tool for supporting distributed agile teams who applies the planning poker technique to perform collaborative user story estimation. The planning poker technique builds on the combination of multiple expert opinions, represented using the visual metaphor of poker cards, which results in quick but reliable estimates.
Mike Cohn wrote an interesting post where he discusses he allows or even encourages to estimate with story points as large as 20, 40, and 100. He explains that they are useful when you need first and not necessarily precise estimate of the general size of a new project being considered.