Skip to main content

Posts

Showing posts from February, 2010

Estimation Poker

Estimation is a necessary part of software development. Product owners want to know how much work can get done by a deadline, project managers need to make commitments, and developers want to know if they committed to a reasonable amount of work.  While estimates are often inaccurate, estimates  provide landmarks along the way of a project to gauge progress. So, estimates are an inevitable, and useful part of the software development process. Many complain that the process of getting to those estimates, estimation, takes too long, so planning sessions are cut short and teams don't have enough time to discuss issues that have uncertainty. By appropriate use of planning poker, you can balance the needs for good estimates while minimizing time spent estimating.

Sometimes when a team is asked to estimate a backlog item, one or more people with expertise in an area are asked to estimate the item, but this is not the best way for an agile team  to get a good estimate.

There are benefits…

The Indivisible Task

One of the things that makes agile work well is a daily sense of progress that can be reflected in, for example,  a burn-down chart.  For burn-down charts to be meaningful, the estimate of amount of work remaining in a sprint need to be accurate. Re-estimating work remaining in a task is helpful,  but the best measure of progress is the binary "done/not done" state of the items in your backlog.

Assuming that you have a clear definition of "done" for a task,  it's easiest to measure progress when you have tasks that are small enough that you can mark them complete on a daily (or more frequent) basis. Breaking work down into a reasonable number of reasonably sized tasks is something many find challenging. (Note: I'm talking here about development tasks as part of a sprint backlog, rather than splitting User Stories in a product backlog, though there are some parallels.)

 I've worked on teams when people refused to break down large task into 1-day or smal…

97 Things Every Programmer Should Know is Done

The book 97 Things Every Programmer Should Know: Collective Wisdom from the Experts is finally available, and the title is on the mark.

Kevlin Henney, who I first met at the 1998 PLoP conference, asked me to participate in this project  in September of 2008.  I am honored to be a part of the list of contributors, which includes Kevlin,  Bob Martin, Michael Feathers, Giovanni Asproni, and many others who have important things to say about how to build great software. Kevlin did an amazing job coordinating and editing, and the the book represents an excellent cross-section of the many contributions that formed the basis for the final version.

Reading this book gives you a chance to learn from the experiences of people who've worked hard not just at writing good code, but at creating good software systems. Some of the advice may be things you already know. Some items may be surprising. Read this book to learn, be challenged, and to understand why programming isn't just about lang…

Tracking what Matters

I'm a big fan of burn-down charts for tracking sprint and release progress.  The basic idea of a burn-down chart is that the team starts with estimates for all of the tasks in the sprint, and then on daily (or more frequent) basis re-estimates the amount of work remaining.

With a burn-down chart, you are tracking the new estimate based on the work that you have done. As you work on the sprint backlog you get a better understanding of the tasks, and thus you can revise estimates for tasks that span more than one day. This is reasonable since the original estimate is, well, an estimate.

Sometimes if you spend 4 hours on an 8 hour task, you'll have 4 hours of work left. Most of the time the time left  will not be the original estimate less the time spent, but more or less. At the end of 4 hours, the remaining work estimate for the same 8 hour task could be 2 hours, or it could be 10 hours if you discovered a snag.  This is important information for everyone involved in the proje…