Seeing the Value in Task Estimates

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a list of task estimate sizes with beta curves overlaidYou might be aware of the ongoing discussions around the #noEstimates movement right now. I have the luxury here of rarely needing to use estimates as commitments to management but I usually (not always) still ask my teams to estimate their tasks.

My consistently positive experiences so far mean I’m unlikely to stop any time soon.

3 weeks ago I joined a new team. I decided I wanted to get back into the commercial side of the business for a while so I’ve joined our Sales Operations team. (Think DevOps but for sales admin, systems, reporting, targeting & metrics).

Fortunately for me the current manager of the team who took the role on a month or so earlier is amazing. She has so much sales domain knowledge, an instinct for what’s going on and deeply understands what’s needed by our customers (the sales teams).

I’d been working with her informally for a while getting her up to speed on agile project management so by the time I joined the team already had a basic whiteboard in place, were having effective daily standups and were tracking tasks.

The big problem with an ops team is balancing strategic and tactical work. Right now the work is all tactical, urgent items come in daily at the cost of important but less urgent work.

We’re also facing capacity issues with the team and much of the work is all flowing to a single domain expert who’s due to go on leave for a few months this Summer – again a common problem in ops teams.

I observed the movement of tasks on the team board for a week to understand how things were running, spot what was flowing well and what was blocked. As I observed I noted challenges being faced and possible improvements to make. By the end of the week I started implementing a series of near-daily changes – My approach was very similar to that taken in “a year of whiteboard evolution“.

Since the start of April we’ve made 17 “tweaks” to the way the team works and have a backlog of nearly 30 more.

Last week we started adding estimates to tasks.

I trained the team on task estimation – it took less than 10 minutes to explain after one of our standups. The technical details on how I teach this are in my post on story points. But there’s more than just the technical aspect. (In fact the technicalities are secondary to be honest)

Here’s the human side of task estimation…

  • Tasks are estimated in what I describe as “day fragments” – essentially an effort hours equivalent of story points. These are periods of time “small enough to fit in your head”.
  • The distribution scale for task estimates I recommend is always the same. 0.5, 1, 2, 4, 8, 16, 24 hours. (the last 3 are 1, 2 and 3 days) – It’s rare to see a task with a “24” on it. This offers the same kind of declining precision we see with Fibonacci-based story point estimates.
  • For the level of accuracy & precision we’re after I recommend spending less than 30 seconds to provide an estimate for any task. (Usually more like 5-10)
  • If you can’t provide an estimate then you’re missing a task somewhere on understanding what’s needed.
  • Any task of size 8 or more is probably more than one task.
  • Simply having an estimate on a task makes it easier to start work on – especially if the estimate is small (this is one of the tactics in the Cracking Big Rocks card deck)
  • By having an estimate, you have a better idea of when you’ll be done based on other commitments and activities, this means you can manage expectations better.
  • The estimates don’t need to be accurate but the more often you estimate, the better you get at it.
  • When a task is “done”, we re-check the estimate but we only change the number if the result is wildly off. E.g. if a 1 day task takes just an hour or vice versa. And we only do this to learn, understand and improve, not to worry or blame.

So why is this worth doing?

Within a day we were already seeing improvements to our flow of work and after a week we had results to show for it.

  • The majority of tasks fell into the 0.5 or 1 hour buckets – a sign of lots of reactive small items.
  • Tasks with estimates of 8 hours or more (1 day’s effort) were consistently “stuck”.
  • We spotted many small tasks jumping the queue ahead of larger more important items despite not being urgent. (Because they were easier to deliver and well-understood)
  • Vague tasks that had been hanging around for weeks were pulled off of the board and replaced with a series more concrete smaller actions. (I didn’t even have to do any prompting)
  • Tasks that still couldn’t be estimated spawned 0.5 or 1 hour tasks to figure out what needed to be done.
  • Large blocked items started moving again.
  • Team members were more confident in what could be achieved and when.
  • We can start capacity planning and gathering data for defining service level agreements and planning more strategic work.

I’m not saying you have to estimate tasks but I strongly believe in the benefits they provide internally to a team.

If you’re not doing so already, try a little simple education with your teams and then run an experiment for a while. You can always stop if it’s not working for you.

 

 

A quick update – Janne Sinivirta pointed out that “none of the benefits seem to be from estimates, rather about task breakdown and understanding the tasks.”

He’s got a good point. This is a key thing for me about task estimation. It highlights quickly what you do & don’t understand. The value is at least partially in estimating, not estimates. (Much like the act of planning vs following a plan). Although by adding the estimates to tasks on the wall we could quickly see patterns in flow of tasks that were less clear before and act sooner.

As we move from tactical to strategic work I expect we’ll still need those numbers to help inform how much of our time we need to spend on reactive work. (In most teams I’ve worked in it’s historically about 20% but it’s looking like much more than that here so far).

Martin Burns also highlighted that understanding and breaking down tasks is where much of the work lies. The equivalent of that in this team is in recognising what needs investigation and discussion with users and what doesn’t and adding tasks for those items.

Swimlane Sizing – Complete & Fast Backlog Estimation

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Thanks to Adrian Wible for sharing this tip when I was in Nevada a couple of years ago. It’s now one of the most powerful simple tools I have at my disposal. I use it frequently with teams to rapidly size their backlogs and recalibrate their sizing.

This can be used with teams at any experience level but works with least pain if teams aren’t used to story points beforehand.

Teams new to story-points (or even working together) often get hung up on the numbers themselves and instinctively want to start converting to hours, ideal days, elapsed days or similar. The value of story points for teams during estimation sessions is in the relative sizing, not the actual size.

This approach keeps numbers entirely out of the mix until the end and allows participants to focus solely on the relative sizing of stories.

Once we’re over the relative sizing hurdle, adding numbers becomes a straightforward activity.

I’ve done this same activity with electronic tools but I’ll describe the manual version here…

Preparation:

Get your deck of incomplete user stories on readable cards or stickies.

If you also have a couple you have completed, these are useful triangulation points but not mandatory

In a room with your team, get yourself a large flat clear surface. I recommend tabletops in the middle of a space as you can swarm your whole team around all sides – this isn’t so simple with a wall.

Using string or sticky tape mark out 8 “swim-lanes” on the table (Requires 7 lines)

Your table should look something like this.blank table

Don’t put any labels on the swim lanes

 

 

 

 

Activity:

Divide the deck of stories amongst your team and ask members to spend a maximum of 5 minutes silently placing their stories in the swim lanes – with stories of increasing size from left to right.  E.g. smallest stories in the left-most lane.

You might want to lead the team through the first 1 or 2 random stories to give them some anchors or triangulation points to work from.

Don’t say anything about story points or numbers, if anyone asks just reiterate we’re looking for size relative only to each other.

If needed; guidance on complete unknown stories at this point should be to assume they are “very large”. The next round of sequencing will allow others to move them if they feel confident in doing so.

Once all stories are placed, you’ll probably have some “clumping” of stories, as in the table here. (assume X’s are story cards).

Give the team 5-10 minutes to again silently move any stories to different lanes where they feel their size relative to others makes them more closely aligned to those in another lane (stories must be wholly in a single lane – no overlaps).

Encourage team members to quickly look at and consider the location of each story on the table.

A team may occasionally find a deadlock where a story is “stuck” moving back & forth between lanes, you may intervene, pull the card out for discussion or allow the time boxing to encourage the card into a single location. Generally if there’s uncertainty, I choose the larger option but the last step of the process will resolve these.

Your table should now look something like the example here.

Once all the cards are placed and reviewed, ask the team to rate their satisfaction/confidence on the relative sizing and placement of the cards (use a scale of 1-5). For any team members indicating a low satisfaction level (1 or 2), ask them to describe their concern and for the team to decide upon how to act (either move a card or validate its current position). Time box this to 2 minutes per team member if possible. Use this opportunity to re-place any deadlocked stories – if a team really can’t decide, be cautious and go for the larger option.

Once relative sizing is agreed with a reasonable level of confidence for the whole team it’s time for a couple more questions.

For all the stories in the left-most column, do you think you’ll be working on anything smaller?

If the answer is “yes”, call this column 3 or 5; if the answer is “no”, call this column 1 or 2 (a single number from these options – use your judgement and instinct).

Now assign remaining numbers across the top of the columns using a subset of the common modified Fibonacci sequence used for story point estimation: (0, 0.5, 1, 2, 3, 5, 8, 13, 20, 40, 100, !/?)

This will give you a table of stories much like one of the following…

 

 

 

 

 

 

(I usually prefer the far-right column remains unsized to be broken down further to make it clear that this is a coarse exercise and cannot be used for commitments).

That’s it! You’ve just estimated & sized (using story points) your backlog in well under an hour.

It’s coarse, quick and dirty but chances are that even when you learn more, most of these won’t change relative to those in other columns .

More Depth:

The use of “silent sorting” is a powerful practice for agile teams. It removes debate and ensures focused thinking however in this example its use coupled with the lack of numbers is to avoid a common problem with inexperienced estimation teams during planning poker exercises known as “anchoring”. This is where an individual on a team will speak up with their view on what size a story should be before the remainder of the team have selected their view on size therefore influencing and anchoring all others estimates for the same story to a given point.

If you reuse this approach for additional rounds of backlog items I recommend preserving some of the older stories in the swim lanes to provide triangulation points for newer stories. Without these anchors your team’s velocity and estimation may see large shifts and greater unpredictability based on the shape of the new backlog.

Teams will quickly get used to which numbers match which lanes. This practice is still valuable however you may need to encourage teams to remain focused on relative sizes and not the numbers.

I generally hold the following views (and have found these actually do transfer well across teams)

  • 5 is typically a “medium” sized story for a sprint
  • Anything greater than 8-13 requires further decomposition
  • Seriously consider also decomposing stories of size 8-13
  • Anything greater than 20 is in reality an unknown needing further investigation and decomposition before it can be sized sensibly.

These views can in themselves anchor others’ estimates towards some specific numbers. As a facilitator an awareness of the range of numbers used and their meanings is useful but be cautious that this information does not influence the outcome of the team’s process.

Update: March 2015 – 4 years after posting this article it’s still the second-most viewed page on the site. I’ve now added a second article offering some more theory to help explain how swim lanes and story points hang together with traditional estimation concepts.

10 Minute Test Plans

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Struggling to introduce TDD or Acceptance Testing? Here’s a really powerful simple first step that you can perform immediately – How to get your development teams “thinking” about tests and how to test with little or no negative impact and a few seconds setup time.

This assumes you’ve already broken out your story/feature/activity into developer-sized tasks.

  1. Push the keyboard away and get a sheet of A4 or Letter paper and a pen or pencil.
  2. Draw 2 lines to Divide the paper into 3 roughly similar sized areas.
  3. Pair up with the developer who’s going to work on a task.
  4. Start a timer –  you have 10 minutes.
  5. Spend 3 minutes listing out as many “pass” cases as you can think of between you – all those simple “happy path” things.
  6. Spend 3 minutes listing out as many “fail” cases as you can think of – bad inputs, exceptions etc.
  7. Spend 4 minutes thinking of all the boundary cases you can think of – e.g. date/time/time zone, rounding, location etc. Often these boundaries depend on your problem domain.
  8. That’s it – you’re done!

OK, this isn’t going to give you perfect code and it does take a bit of practice. Try not to agonize too much about whether these are unit, functional or acceptance tests for now. We’re still learning to fly here.

Much as standing up collaborating at a whiteboard uses a different part of your brain to coding; paring up, brainstorming and writing with a good old pencil & paper does a similar job. The discipline of not touching the code for a short period of time and thinking about how you’re going to test and what could go right or wrong will significantly improve the quality of what you produce – it usually makes the coding easier too.

Better still – you should now have your first unit tests to write! – pick the simplest ones you have on there and get them working! (I usually start with input validation. I know it’s not directly related to end user value but once I get a good grasp on inputs the rest fits in my head more easily.)