Read my latest article: 8 things I look for in a Ruby on Rails app (posted Thu, 06 Jul 2017 17:59:00 GMT)

Estimating versus Timeboxing, part 1

Posted by Wed, 10 Jun 2009 23:29:00 GMT

As if delivering projects wasn’t hard enough. Delivering projects on time is even harder. As practitioners, we’re all responsible for measuring up the obstacles in front of us and are accountable to those measurements. At least, we should be.

One of those measurements is time. Time is a funny thing. People have a lot of interesting things to say about time. Some say that it’s one of the most valuable things that we have… but I’ll avoid diving into a philosophical discussion for now.

What I wanted to talk about was project estimation. Specifically, estimates for deliverables. For the past several years, our team has put a lot of effort into becoming more accurate in our time estimating skills. Despite analyzing how often we over and/or underestimate the time each of us believes it’ll take to complete a task, we find ourselves coming back to the drawing board.

A few things that we’ve learned.

  • Tasks that we believe will take a few days/week/more to complete are often underestimated
  • Tasks that we believe will take less than a few hours are often more accurate or overestimated
  • Too many tasks were completed with a bigger budget than was necessary (lower ROI)
  • A lot of time was spent working on requirements refining to get better estimates

When we began to step back from this and look for patterns, we found that several of the tasks that we would budget hours for (versus estimate hours for) were proving to be more accurate. This approach is most commonly known as timeboxing. With timeboxing, we can place a dollar value on a specific task and work within that constraint. For example, with our clients, both parties can come to the conclusion that, “we believe that it’s worth up to $800 to implement this new functionality.” With that, we’re able take that dollar amount and figure out how many hours to box ourselves within.

The underlying question to our client with each change/feature request is, “How valuable is this to your business at this point in time?” Whereas, with a typical approach to time estimates, a client comes to you with a list of changes/features and you provide them with time estimates. “We estimate that it’ll take 6 hours at $200/hour for feature X and we’d do it like this…” The client will have to evaluate your estimate and figure out if it’s worth $1200 and make a decision. They can respond with, “no, that’s too expensive, can we do it for less?” The following steps would entail your team trying to find ways to reduce your estimate.

While these two paths might seem very similar, it’s been my experience that the standard approach to estimating takes more time for negotiating the terms of the agreement.

However, with timeboxing, you are asking your client to provide you with an initial budget. This will completely change how you respond to the feature request. When you have a timebox, from the moment that you begin to evaluate the request, your brain will add the necessary constraints to keep things within scope.

Through this process, we’ve revamped our estimating process so that as we’re building our iteration costs for clients. For each deliverable, we break down a series of objectives/tasks and apply timeboxes to each of those while knowing what the budget is for the deliverable as a whole. Usually, the deliverable is directly related to the request that came from our client with a budget. The process is completely transparent and our team is responsible for working within those constraints.

..and as we’ve learned from Ruby on Rails, constraints can be extremely beneficial.

While I don’t have all the answers yet, my goal is to share some of my experiences and lessons on the topic. I’d love to hear about how you’re adopting timeboxing in your project planning and estimating process.

Anyhow, just some thoughts that I wanted to share. More to come…

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The Art of Delivery, part 2

Posted by Thu, 22 May 2008 18:42:00 GMT

Two years ago, I wrote an article titled, The Art of Delivery. I wanted to post a few updates based on how our process has evolved since then (and continues to).

Over the past few years, we’ve been fortunate enough to work on quite a diverse collection of projects. This has enabled us to work with many different clients and solicit feedback on our process. This has given us an opportunity to evolve a set of best practices that fulfills the long-term project goals/budgets of our client while making sure that we’re able to maintain a design and development process that is agile.

As I’ve mentioned in previous posts, our team typically bills work per-iteration on projects rather than per-hour or a flat-bid per-project. Since iterations are bite-sized pieces of the entire project and limited to 1-2 weeks, our teams estimates are much more accurate and we’re able to keep things rolling and on track.

stay on track

The basic structure of our project looks like this.

  • A Project has many releases
  • A Release has many iterations
  • An Iteration has many deliverables
  • A Deliverable has many tasks

Before we begin working on an iteration, we outline a set of goals that we want to create solutions for. This process comes out of discussions between our client and us until we agree on what is the highest value/most critical to the success of the project, based on our shared understanding of where we are today. These goals translate into Deliverables, which in a typical iteration might require Interaction Design, Interface Design, or Development. We tend to break our process up into stages so that Interaction Design on Module XYZ would be implemented in a following iteration. This is because it’s unrealistic to expect someone to provide an accurate estimate on how long it’ll take to implement something before you know how people will interact with it.

Within any given iteration, our team is spread across several sets of deliverables. As a team, we breakdown these deliverables into smaller sets of tasks. It’s our aim to keep tasks smaller than a full days worth of work as it’s much easier to measure progress across the iteration when we can track tasks at a granular level.

Essentially, tasks are the individual steps needed to achieve these goals. We don’t go out of our way to list each one of those during an estimate process as some tasks take less time than it takes to generate an estimate for them. Each person providing estimates should avoid getting too granular and aim to find a good balance that compliments their workflow.

Like most things… mileage may vary.

Through this process, we can get calculate the estimated costs for each deliverable, which then provides us an cost for the entire iteration. In addition to deliverables, we also budget a set of hours/days so that we can be compensated for handling small requests, bug fixes, and project management. It’s important to factor these things into your process.

In future posts, I’ll discuss how we’re handling this process while working on multiple projects… as that’s where it can chaos can start if you’re not careful. ;-)


How does your team work? As we’re always evolving our process in an effort so that we can be more efficient and speed up our delivery cycle, I’d love to learn from those in the community.