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Agile Estimation Techniques | Scrum Estimation Techniques

by StarAgile

February 26, 2020
Category Agile and Scrum


The very word estimate means to guess. It is important to guess how to handle things to plan and execute rightly. This step is part of every SDLC. When we talk about the agile iterative method it becomes even more dynamic and hence a proper estimation will lead to the right planning and hence execution on-time. This will help in saving both money and time. In order to carry out the right budgeting and allocating resources to a project, user story during every sprint is important. 

If you are a beginner in this, then stay assured that you can collect details about different estimation techniques and how to execute them from this blog. We suggest you try all the techniques given below in each sprint to practically understand their pros and cons. But, before that understand which agile estimation technique you should use based on the team size and item numbers. 


1. Planning Poker

Needless to say, all of you might have heard this name. It is similar to playing poker games. Yes, play cards while you estimate time and prioritize the PBIs. Each set of cards with contain 12 cards namely 0, ½, 1, 2, 3, 5, 8, 13, 21, 34, ? and coffee mug etc. Every estimator will be given with a set of cards and the user story selected will be explained by the PO. The team will seek clarification before they choose the card to estimate the time for completing the task. 

Then every estimator will independently choose one card and the others will not know what one has chosen. Later every card will be flipped open to know the right estimate. If all have chosen the same card, then it will be confirmed, but those who have a disagreement and have chosen cards with different values will explain and come to a consensus to choose cards again until all have agreed on the same card. This process will be repeated for each story point required to be completed during one sprint.

This method best suits for a small team with minimal user points. 

2. The Bucket System

Extension of PP when there is a large number of items and the team is large too.

Keep PP as the base and make many buckets in series. The group will estimate every item and place them in the buckets. Before that write all items on the cards and select one item and keep in one bucket for reference. Now, collect another one item and read it aloud so that the team will decide on the relative position to choose a bucket for that item. Then do the same for the third item and so on. Now, check the items based on the size compared with the reference item and bucket size to divide and conquer the priority of the product backlog. 

3. Large/Uncertain/Small - LUS

The simplest form of a bucket system is the LUS system. The team will categorize the item as either large or small. When they are not sure they put it is uncertain. Later it is checked to provide clarity about the uncertain items to place them in large or small. Finally, the execution starts based on the size of the item. 

Smaller groups with moderate and comparable items can follow this technique. 

4. T-Shirt Sizes

In this method, the story point is sized based on the relative estimation. Here t-shirt sizes are used in the place of cards with values as discussed above. The size of the t-shirt varies from XS to XXXL. You can relate better when we number t-shirts with sizes. For instance, a Small size t-shirt means value 1 to 3. The medium size is for story point values 5 – 8 and so on. The process remains the same as PP and the estimators will agree on the same size for each user story and start working. 

This is suitable to estimate large items and large backlogs. 

5. Dot Voting

Small items and a simple method to estimate can be done using a dot voting method. 

All the participants will use small stickers to vote for every item. The item that has received more dots will get the first priority. This method can be used for large groups as well. 

6. Affinity Mapping

Similar items are grouped together. This will first help the team to separate them as small and large. Then either the PP or t-shirt method is used based on the number of items to give each item a specific value. 

Small groups with smaller items can best choose this method to first categorize and then add value. 

7. Ordering method

First, each item is placed but with a random ordering on a scale. The scale measures from smaller value to higher. Then the participant is asked to move the item on the scale one up or one down. Based on their expertise each participant will make the move and thus the item will get the correct value at one point.  

Small groups but an expert group can choose this method even for larger items. They will know the right order for execution. With limited time they can select the items and prioritize them. 

Estimation Units

The estimation units are primarily the story points. After the estimate is completed based on the story points it can be converted to real-time. 

For instance, in PP we choose each story point and provide them value like 1, 3, 8, etc. Based on the item it is assigned a value and then the time taken to complete each task is decided. It is not possible to confirm the man-hour for each task completion and hence estimation is carried out based on the story points. 

Likewise, in the t-shirt estimation technique, the size of the t-shirt is the measuring unit. In general foot-pounds, nebulous units of time (NUTS), and gummi bears can be used as an arbitrary token. 

Estimating Schedule and Budgeting

Soon after estimation is over it allows for easy scheduling and hence budgeting. Thus by choosing the right agile estimation technique you can make a correct schedule and allocate budgets. 

Find the example given below to schedule and budget for your projects. 

If your team has finalized 3 items to be completed in a 1-week sprint, then know their value points. In PP, you need to add their value 1, 2, and 3 which means a total of 6 points. If your team has completed only 2 items, then it is considered as not completed. 

This means you need to determine the schedule for effective budgeting. So check the team’s performance for 3 consecutive iterations. Find the average of all three points. This will give you an idea about the team performance. Based on the story value and the average time taken to complete you can now allocate budget. 

Budget calculation – (cost of each point X total point) + miscellaneous expenses 

This will save money as you will now know the time taken to complete the entire project. You will know how many sprints are required to assign the product backlogs accordingly. 

Conclusion 

Thus estimation technique plays a vital role in the agile methodology. Choose the correct technique to save resources time and company expenses. As mentioned already, try one technique each in sprint to understand which works best with your team. 

If you want to understand estimation techniques in detail attend StarAgile Scrum Master Certification or call us on +91 – 80502 05233

Abbreviation used this blog

  • Product Owner – PO
  • Product Backlog Item – PBI
  • Planning Poker - PP