New

Accurately estimate complex projects in seven steps within one hour.

The process described here allows you to create a Rough Order of Magnitude (ROM) estimate in less than one hour, which has proven to be +-80% accurate to the final figures based on incomplete information. The process allows you to jump from a high level of uncertainty as visualized in the Cone of 

Uncertainty to a low level of uncertainty in 7 simple steps.

Overview

This practice should be undertake when the following 2 conditions exist

• This effort / sizing estimate must be provided soon as possible.
• This effort / sizing estimate must be as accurate as possible.

The process lives up to its name and can be completed rapidly. The facilitator jumps between tasks/epics/topics in rapid succession..

We start with a Work Breakdown Structure (WBS) diagram drawn on whiteboard. Each one is drawn in a boxed title regardless of whether they are Agile Themes, Epics, User Stories or WBS child elements.

The starting point, with the WBS created

Acknowledge the anchoring bias​​

Step 2 - 1 minute

It is important to note that we do not use numbers at this stage, as this may cause the team to fixate on a value. We then move horizontally across until each WBS node has a t-shirt size value..

Realign high level thinking​

Step 1 - 4 minutes

We then agree upon a preliminary Definition of Done (DOD). The DOD is the list of tasks that must be undertaken before a User Story (or task) is considered as complete. Analysis, Development, Testing, Documentation & Peer review are often found in the DOD. Once defined, on Pass 1 [5 minutes], we then rapidly work vertically down the parent / child nodes of the WBS, sizing each node (Epic or User Story) as Small (S), Medium (M), Large (L) or Extra Large (XL).

First size each child task/epic & then move across

Put similar tasks side by side​

Step 3 - 8 minutes

Now that each node has a size, we process the WBS again. We ask if the sizes of each WBS that are currently listed with the same size is relatively the same size as another with that value.

Pass 2 [2 minutes]: Is this Small WBS Epic comparable to this Small WBS Epic? As much as possible, compare each Small WBS Epic with all other Small WBS Epics.

Pass 3 [2 minutes]: Is this Medium WBS Epic comparable to this Medium WBS Epic? As much as possible, compare each Medium WBS Epic with all other Medium WBS Epics.

Pass 4 [2 minutes]: Is this Large WBS Epic comparable to this Large WBS Epic? As much as possible, compare each Large WBS Epic with all other Large WBS Epics.

Pass 5 [2 minutes]: Is this Extra Large WBS Epic comparable to this Extra Large WBS Epic? As much as possible, compare each Extra Large WBS Epic with all other Extra Large WBS Epics.

As facilitator, its important to try to find the best example of a Small, Medium, Large and Extra Large. You will make use of these later. Its also important to look out for (and mentally note) the ones that the team are hesitant about. Which Small, may be a Medium. Which Medium may be a Small, or may be a Large etc.

Choose a task and quickly compare to other comparative sized tasks

Inferential analysis of different sizes tasks​

Step 4 - 17 minutes

Then we look to compare the different sizes with each other.

Pass 6 [5 minutes]: Is this Small WBS Epic comparable to this Medium WBS Epic? Use the ideal ‘Small’ that you made note of before. Also flip between the borderline Small WBS Epics. Test and verify each one. Don’t be afraid to change a ‘Small’ to a ‘Medium’ if needs be.

Pass 7 [5 minutes]: Is this Medium WBS Epic comparable to this Large WBS Epic? Use the ideal ‘Medium’ that you made note of before. Also flip between the borderline Medium WBS Epics. Test and verify each one. Don’t be afraid to change a ‘Medium’ to a ‘Large’ or ‘Small’ if needs be.

Pass 8 [5 minutes]: Is this Large WBS Epic comparable to this Extra Large WBS Epic? Use the ideal ‘Large’ that you made note of before. Also flip between the borderline Large WBS Epics. Test and verify each one. Don’t be afraid to change a ‘Large’ to an ‘Extra Large’ or ‘Medium’ if needs be.

Pass 9 [2 minutes]: Is this Extra Large WBS Epic comparable to this Medium WBS Epic? Don’t be afraid to change them.

Choose a task and quickly compare to other tasks sized smaller or larger than it

Define the estimates range​

Step 5 - 10 minutes

Most developers do not like to give estimates. And with good reason. To get around this problem, after reviewing the Definition of Done again, we ask the team to provide two estimates for a Small, a Medium, a Large and an Extra Large. We ask for the Lower Bound (smallest number of that possible size) and the Upper Bound (largest number of that possible size). Note that the number provided can be either a Story Point or a Man Day Estimate. Ensure that the team agree on which beforehand. We then compare each Epics against these ranges to ensure that the Epic fits within that range. If not, then we look to either move the Epic to a different size, or adjust the range accordingly.

Define the range of Small, Medium, Large & Extra Large

Leverage the mean of items​​

Step 6 - 15 minutes

Having reviewed all of the Epics against ranges, we then sometimes go further and either determine the average or the median average of each Size and determine if they roughly fit against each Epic within the WBS.

Note the median average of each size

Yield the numbers​

Step 7 - 5 minutes

Finally we attribute the numbers to the WBS Epics and total them. We review the notes that were taken and determine where risk lies within the Epics. We determine if contingency is needed and usually calculate this as a percentage of the total. This provides you with a vastly more accurate ROM estimate then the traditional ROM estimate.

Attribute numbers to tasks/epics & add them together.

Address

Dublin, Ireland

Contact

[email protected]

Menu

Follow me