Estimation

Affinity Estimating

In Affinity Estimation, all participants estimate different items at the same time and exceptions are discussed in more detail. It’s great for large backlogs or initial/distant estimates.

Pros/Cons

  • It is very fast, allowing to estimate large backlogs very quickly
  • It highlights assumptions and misinterpretations by exception
  • Everyone is involved in the estimate
  • It is very easy for experts to ‘lead’ the estimating

Tools

  • Set of estimation units in card form (Fibonacci, T-Shirt Sizes)
  • Additional recommended cards:
    • Infinite (Too big to estimate)
    • Question (Unable to estimate with existing information)
    • Red, Amber and Green cards for confidence estimating
  • A number of items to estimate, printed or written on pieces of paper/card

Some coaches may suggest doing this in complete silence, but in my personal experience I have found the conversation that results from this exercise helps create some shared understanding of the work which is worth the extra time it takes.

Flow

To set up, create the following - probably on a large flat surface:

If you have no reference point, start by finding a typical mid-complexity piece of work that you’re pretty confident with and place that in the middle of the wall/table, place that in the 5 column in the high confidence row.

Next all team members at once consider other work items and add this to the wall one by one, thinking about the relative complexity of the other items and how confident you are with your estimate.

Keep in mind that for the work item to be a complexity ‘5’ this should be about the same as a ‘3’ and a ‘2’ put together.

Any person in the estimating process can move any work item at any time, even if they disagree, however, if you find a work item moves back and forth, this should be discussed. This avoids unnecessary conversation about items that everyone agrees are the same size.

If someone feels they are unable to estimate, they can move the item to the question column. Then someone else can move it out of the question column providing they explain their estimate.

The above diagram shows an example outcome from an affinity estimation session. It’s quite common to add a numerical modifier to the levels of confidence when using the estimates to predict. For example:

  • Red = 2x Modifier
  • Amber = 1.5x Modifier
  • Green = 1x Modifier

We would then calculate optimistic-pessimistic estimates as follows:

As a result this total estimate for the work that we are able to estimate is 52-92points. With the knowledge that there are 2 items that need breaking down and adding to the estimate and 1 item that needs more information.

Do you think Affinity Estimation would work for your organisation? What problems could you forsee?

Planning Poker / Delphi Estimating

Planning poker is a consensus estimate generated through multiple rounds of synchronised ‘reveals’. It’s great for thrashing out detail and shared understanding.

Pros/Cons:

  • Multiple people estimate a work item at the same time, avoiding 1 expert ‘leading’ the others
  • It highlights assumptions and misinterpretations
  • It encourages group discussion, which increases the accuracy of an estimate
  • It takes a long time to estimate a large backlog

Tools

  • 1 set of estimation units in card form (Fibonacci, T-Shirt Sizes) for each team member
  • Additional recommended cards (1 set for each team member):
    • Infinite (Too big to estimate)
    • Question (Unable to estimate with existing information)
    • Red, Amber and Green cards for confidence estimating
  • A number of items to estimate, printed or written on pieces of paper/card

Flow:

  • Someone reads the description of the work item to the team
  • The team consider the complexity of the work and their confidence level. They collect 1 estimate and 1 confidence level card (Red = Low, Amber = Medium, Green = High)
  • When someone feels they have a number they raise their 2 cards in the air to show they are ready to estimate
  • When everyone has their cards in the air, a rock-paper-scissors style 1-2-3 is called and everyone shows their estimate using their hands
  • If the estimate is inconsistent around the room, the highest and lowest estimates are compared and discussed*
  • The process is repeated until a consensus is made
  • The complexity estimate once agreed is written on the work item
  • Choose the next work item and follow the steps again

*If there is inconsistency, for example a ‘3’ and a ‘8’ estimate confidence this is a good cause for discussion, the team member estimating ‘8’ may have more detail on why a work item is more complex due to information that others may not be aware of or know that this would rely on another piece of work being done. Alternatively, the team member estimating ‘3’ may have knowledge of a similar work item that has been solved before and therefore makes this work item easier.

This is especially true when stakeholders estimate differently to team members as this can highlight a misunderstanding in requirements or complexity.

10 Tips to Get The Most Out of Your Estimation Sessions

Estimation can be a real pain in the backside. Here are our top ten tips for estimation in an Agile environment:

  • Understand the value that estimating is bringing your team and organisation
  • Don't use an electronic tool during your estimation sessions. It always takes longer. If you use an electronic tool to track your work, type up your results after.
  • Timebox each estimate. If it's taking too long, park it and discuss outside of the meeting with less people until it's sufficiently detailed to estimate.
  • Don't estimate anything you don't have to.
  • Always prioritise estimates for work you are doing sooner rather than later.
  • Be honest in your estimates. Have a reference item to compare you estimates to so you can validate.
  • Ask questions if you don't understand the work. If you're worried you're taking up too much time by asking questions find someone after and ask to pair.
  • I like the Product Owner's to estimate too. It helps show any discrepencies in understanding. The team's estimate is still the estimate.
  • Involve several people and disciplines in estimating your work.
  • Don't stress about estimates. By definition they are inaccurate.

What top tips have you got? We'd love to hear them.