Introduction to Planning Poker

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What is Planning Poker?

Planning Poker (also called “Scrum Poker”) is the preferred estimation technique for Scrum. Each user

story is estimated using a series of numbers that (a) are integers and (b) become more widely spaced as

the series increases. The number series used most often in Poker Planning is the Fibonacci Series.

What is the Fibonacci Series?

Here is the beginning of the Fibonacci Series …

1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, …

Each number in the series is the sum of the two preceding numbers. The Fibonacci Series is highly effective for estimating for several reasons.

1. It reflects the fact that as estimated effort increases, the uncertainty in that estimate also

increases.

2. If you believe the effort may be more than a given number in the series, your next available

choice will be at a significant distance from that number. For example, if you think the effort

may be greater than a 13, your next available choice is 21; there is no option to “bump” a 13 up

to a 14 or a 15.

3. Practice using the series enforces more “hard-nosed” realistic estimation; over time, “surprises” in actual effort should become more rare.

What Do the Numbers Mean?

The numbers should not be thought of as representing hours, days or some other time interval. They are

meant to “size” the work: in other words, after considering the scale and complexity of effort to deliver a user story, each team member assigns a value from the Fibonacci Series.

One way to use Fibonacci values is as follows:

1. Set an upper bound on the series to be used by your organization (an upper limit of 144 would

not be unusual.)

2. A value of 1 should represent the smallest discrete piece of work needed to deliver against a

user story.

3. A value of 144 would represent the largest possible development effort achievable by the team

within the cadence of your Scrum process. (In the rare cases where you exceed 144, the user

story should be decomposed further into chunks that can be delivered within your Scrum cadence.)

Over time everyone in the Development organization will develop a common understanding of what the numbers signify, and will become proficient in their application.

Introduction to Planning Poker

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How do I Play?

As with all Scrum ceremonies, Poker Planning sessions work best when they are time boxed (they should

also be recorded.) Sessions are often conducted using playing cards with Fibonacci numbers printed on

them. After the team reviews the user story together, each member places their card face -down. When

everyone has made an estimate, the cards are turned over. If all the estimates are in broad agreement,

the poker session may conclude. If there are widely different estimates, this is often an opportunity to

surface knowledge held by one or two team members regarding complexities and/or dependencies unknown to the rest of the team.

There’s an app for that.

In addition to physical poker cards, there are many Planning Poker apps now available for all major smart phone platforms; many of these apps are free.

Notes.

When choosing a Fibonacci number, it is important to consider both the Scale and Complexity of

the user story. An enhancement may be trivial in terms of complexity but may have to be

implemented across multiple releases and applications; similarly, a change may be isolated to

one release of one app (therefore small in scale) but may require highly sophisticated

architecture, coding and testing (high complexity)

Some Planning Poker card sets use a modified Fibonacci series. Whether or not your

organization uses the standard series or some modified series, it would obviously be unwise to mix the two within a single development organization.

Further Reading.

Poker Planning is an example of what is called a Wideband Delphi estimation technique. These emerged

from work done in the late 1960s by the Rand Corporation. See The Delphi Method: An Experimental

Study of Group Opinion at http://www.rand.org/pubs/research_memoranda/RM5888.html.