Backlog estimation is an important project management aspect, especially in Scrum-based product development. Backlog estimation helps teams estimate the time/effort required to complete the product backlog items and plan their work accordingly. However, it is seen that many teams face the issue of inaccurate backlog estimates, which leads to missed deadlines, a stressed environment, unhappy stakeholders, and other complications. Therefore, this article intends to discuss the top reasons that lead to inaccurate backlog estimates and also present the possible solutions to avoid them.
There are many reasons that can lead to inaccurate backlog estimates, but below are the eight top reasons that most often results in inaccurate product backlog estimation:
One of the main reasons why teams have inaccurate backlog estimates is unclear user stories. User stories present the requirement of the backlog item from the user's perspective. When user stories are unclear, it makes it difficult for the team to understand what are the expected outcomes. This leads to either overestimation or underestimation.
To fix this issue, teams should be open about when they don't understand the requirements of user stories. Team members should clarify user stories with the Product Owner and ensure they understand the requirements clearly before heading for estimation.
Not all user stories are simple as they seem. Some user stories have dependencies or hidden challenges that usually appear when the team is working on them. Such uncertainties can show up at any time, so if the team hasn't allocated some extra time to combat those complexities, then it results in delays. Therefore, underestimating the complexities of user stories is another potential reason behind inaccurate estimates.
The best way to address uncertainties of user stories is through deep discussions during estimation. When a team conducts thorough discussions around user stories before estimating, it helps to look into the matter from different perspectives. Moreover, the team can break the user story into smaller pieces for proper understanding if the user story is complex. Eventually, this helps teams identify potential roadblocks and provide more realistic estimates of efforts.
Another potential reason behind inaccurate backlog estimates is the use of the wrong estimation technique. There are plenty of estimation techniques that Scrum teams can use, such as Planning Poker, Async Poker, Dot Voting, Affinity Mapping, T-Shirt Sizing, Bucket System, etc. All these techniques have their specific use cases. For example, Planning Poker is best suited for on-premises backlog estimation, Affinity Mapping for large product backlogs, and Async Poker for remote-based estimates. So, which estimation technique works best for the team depends on the team's structure and product backlog. Therefore, using an incorrect estimation technique can lead to inaccurate estimates.
To avoid this issue, the team should closely look into which estimation techniques best suit their work model. They can even test a few estimation techniques until they find the best one. In short, they should pick the more appropriate estimation technique that members are comfortable with, thereby leading to accurate estimates.
Backlog estimation is a collaborative activity where every member provides input, resulting in accurate estimates. However, if only a few team members are part of the estimation process, then it reduces the opinion diversity and comprehensive view of the required effort. Eventually, this can lead to underestimation or overestimation of effort.
Team involvement is directly related to estimation accuracy. During estimation, the whole team or at least all the core team members should be present to comprehensively discuss efforts and potential roadblocks.
Another common reason for inaccurate estimates is overconfidence. Sometimes the team is overconfident about its abilities and underestimates the effort required to complete a user story. A team might assume that it can complete the user story quickly because they have performed similar tasks in the past, but fail to consider the differences between those two stories. So, overconfidence can often lead to inaccurate estimates.
To avoid the unintentional overconfidence aspect, the team should always remain objective when estimating. They should look into the requirements as if they are doing the task for the first time. They should ensure that they have a proper understanding of the task despite having worked on a similar one in the past.
Another major reason behind inaccurate backlog estimates is the emphasis on time-based estimates over effort-based estimates. It is human nature that we intend to estimate everything based on time. For example, “I will complete this task in 30 minutes”. However, product backlog estimation is different and involves uncertainties or complexities that can result in delays. So, if a team estimates backlog in terms of hours or days, it can lead to inaccurate estimates.
The best way to estimate product backlog is to estimate user stories based on the efforts. The team can use story points that reflect the amount of effort required to complete a user story. For example, if one user story is given 5 points while the other is given 3 points, it means the first user story requires more effort. This way, the team gets the margin to address uncertainties and avoid upsetting stakeholders.
In many cases, the team has worked on a similar user story in the past. However, if the team doesn't have access to the reference data at the time of estimation, they cannot identify how that user story went in the past. Owing to that, they can keep making the same mistakes again and again.
To avoid this issue, the Product Owner or other team members must ensure that the reference/historical data related to the current user stories are available for the team to look into while estimating. This way, they can check the velocity and cycle time of past similar user stories and then provide more realistic and accurate estimates.
The length of the product backlog is also related to inaccurate backlog estimates. When the length of the product backlog is large, it means that either the team has to spend hours discussing and estimating backlog items or the team has to use less effective estimation techniques to quickly estimate backlog items. If the team has to spend hours estimating a lengthy product backlog, it can compromise their productivity and focus, thereby leading to inaccurate estimates.
To avoid this issue, the focus should be to keep the length of the product backlog manageable. The Product Owner should only include those items in the backlog that are essential for the product's success. Moreover, the product backlog is not a one-time thing. The Product Owner can add new items to the backlog during the backlog grooming meeting. In short, the target should be to have a manageable product backlog that the team can easily discuss and estimate in 2-4 hours.
It is not necessary that you have accurate backlog estimates all the time. If you are a new Scrum team, involving new members, or dealing with different backlog items, then it is likely that your estimates might not show accurate responses. Besides that, the above reasons are also some main factors behind inaccurate estimates. So, if inaccurate estimates are natural, you should use them as an opportunity to learn from your mistakes, improve your estimates, and have more accurate guesses of efforts. This way, not just will your estimates become accurate, but your team's workflow will also become more efficient.
