# Relative Estimation in Agile Processes

Thu Feb 17 20228 min read

## Why we need estimation?

Without estimates every project seems something like this…

## Why is estimation hard?

There are many reasons why estimation is hard for us. Some top reasons are -

- Naturally, we are not great estimators
- Too many unknowns
- Technology constantly changes
- No two implementations are exactly the same
- External Environment factors

## Why bother estimating?

If estimation is so hard, then why bother estimating at all? The question makes sense, but the major reasons why we need estimations are -

- Make trade-off decisions when choosing among multiple options
- Setting goals with realistic data

## What is Relative Estimation?

Relative estimation is ** one of the several distinct flavors of estimation** used in Agile teams, and consists of estimating tasks or user stories,

**, but**

*not separately and in absolute units of time***or**

*by comparison***of items of equivalent difficulty**

*by grouping*### In English please

What does it mean in simple terms -

- We don’t need to deconstruct the problem to estimate
- Comparing is faster and more accurate
- Learn from previous experience – data driven / experience driven approach
- Sizing in relative terms rather than actual hours
- Get better at estimation with time

## Relative Estimation in real life

Let’s look at some real life examples of Relative Estimations

### Coffee Anyone?

The world runs on coffee. I would be so cranky without my morning cuppa, and I am sure most of us will be like me.

But when we are ordering coffee, are we doing exact calculations?

Are you trying to **estimate how many ml / cc of coffee** each cup holds?

Are you asking **exactly how much** coffee **’M’** holds?

You are making an **imperative decision** based on **previous experience** (’L’ kept me up last night and ‘S’ is too small, hence I will go for ‘M’)

### Making Assumptions - Painting a house

Let’s take one more example.

We want to paint a house.

**Task Details**

The house consists these many rooms

- Three large rooms
- Four medium rooms
- Two small rooms

**Known Facts**

What we already know about the task at hand -

- Painting a medium room takes one week

**Assumptions**

As we are new at this, based on previous experience, we make assumptions

- A big room would take two weeks to paint.
- A small room takes a half week to paint.

**Estimating using assumptions**

Based on the assumptions we made, we can now estimate the total work.

- Painting three big rooms would take six weeks.
- Painting four medium rooms would take four weeks
- Painting the two small rooms would take one week.

Using relative estimates, you could determine that it would take a **total of 11 weeks to paint the house**.

## Relative Sizing

Relative Sizing consists of 2 parts - **Sizing** and **Relative**

### Size

**Effort.**How much work is required to complete this task?**Complexity.**How difficult or complicated is this task?**Uncertainty.**Do we know exactly what must be done to accomplish this task, or will we need to learn as we go?

### Relativity

The ** size is relative** to the

**your team may have on its plate.**

*other stories*### Fruit Salad Game

To understand **relative sizing** better, let’s play a game. Suppose you need to prepare a fruit salad.

Game’s requirements are as follows:

- Prepare a fruit salad
- Several types of fruits
- Each fruit needs to be prepared for the salad
- Each person will be given one fruit at a time
- Must consider the
of preparing it for the fruit salad*effort, complexity, and uncertainty*

Let’s start !!!

#### Step 1: Start with T-Shirt Sizes

Start with T-Shirt Sizes on the board

#### Step 2: Process a familiar fruit

- Start with something familiar – an apple
**We are familiar how to process an apple**- few minutes to remove the core and cut it up- the task is
**not overly complicated** - This becomes your
**baseline - Medium**

#### Step 3: Choose the simplest task

- Choose a
**task which is no-brainer** - Grape is very simple to process and way less complicated than an apple
- This becomes your
**smallest unit - XS**

#### Step 4: Iterate till all done

- Continue the exercise, considering the
**relative effort, complexity, and uncertainty**involved - After all fruits are iterated,
**debate on the distribution** **Adjustments**can be made as**new information and perspectives**are presented

Finally, the ** result is a list of fruits**, each

*sized relative*to the

*others in the salad*.

### Fruit Salad in Real World

The ** first step** is to

**. Find your apple or pear.**

*determine what is a medium project*** Sizing is Relative** – need an anchor or gold standard to compare all stories against it.

** Rule of Thumb**:

*medium story*is one that can be

*completed in a day or two*.

### Fibonacci wears the T-Shirt

**Fibonacci Sequence:**the sequence is created by adding the previous two numbers together (0, 1, 2, 3, 5, 8, 13, etc.)- As
*story size increases*, the*gap between numbers widens* *Massive projects*are much*harder to estimate*to an exact number- Keeps the teams from getting hung up on minor differences

This forces you to ** keep your eyes on the big picture**.

### Benefits of Relative Estimation

- The human brain works well with relative comparison -
**we have an inbuilt sense**of something being relatively bigger or smaller than something else. **Team members are much more comfortable with relative estimation**. Team members*often hesitate to provide estimates*of how long tasks will take to complete. They are aware that they typically*do not have all necessary information at the time of estimating*, and so they*do not feel confident*to say how long a task will take. They feel much*more comfortable*to give their*opinion on whether a task is bigger or smaller*than another task*by comparison*.- Stakeholders or project managers
and breed an expectation that features will be completed in this time, rather than just using them as an input to decision-making.*sometimes mistakenly take time estimates as commitments*.*It is impossible to take relative estimates as time commitments because relative estimates are not measured in time taken* - When asked how long a task will take to complete,
**people sometimes “inflate” time estimates**so that there is*some built-in slack*when*more complex details*become known..*You can avoid this problem with relative estimation* - Relative estimation is proven to be effective and provides more accurate estimates. (Improving Subjective Estimates Using Paired Comparisons, Miranda 2001)

### Relative Estimation Myth Busters

There are many wrong assumptions about Relative Estimations. Some common myths held, which needs to be busted include -

- Relative Sizing
*is not a time commitment* - Accurate Estimates are
*impossible* - Estimate is
*not a guarantee* - Time based estimations
*don’t factor in external factors* - Story points
into hours / days / weeks*cannot be converted* - T-shirt sizes are
– (‘L’ is not equal to twice the effort of ‘M’)*not empirical*

### Confidence v/s Story Points

Confidence and Story Points are ** inversely proportional**. As story points increases, confidence decays exponentially.

## Summary

Few take away from this discussion.

*Relative estimation*is the*process of estimating task completion*by*comparing*them to*previously completed tasks*.- The human brain is
*naturally hard-wired*to*work better*with*relative comparison*. - Relative estimation provides
*better estimates*. - Relative estimation works by
*estimating size first*, so you can*relate this size to a task you have completed previously*. Then you*estimate*how long the task will take to complete by making a*relative comparison to the time taken*to complete this other task. - Relative estimation is
*not absolute commitment of time*. - We get
*better at estimation with practice*.

Hope this helps you to make better estimations.