We have to make estimates with every software development project – how much will it cost, and how long will it take? These estimates provide important information for planning resources, budgeting, and launching purposes. The truth is, however, that development project estimates are not something we’re typically taught. And once we have to do it, we soon realize: Making accurate estimates is very hard.
Why estimating software development time is challenging?
Development projects may include many twists and turns, which make estimating time for tasks and overall project completion challenging. Let’s explore all the reasons why it becomes complicated:В В
- Adding and changing criterionВ
Software projects are complex. They consist of many parts, including specifying and identifying suitable resources, planning and designing, programming and documenting, and continuous testing and bug fixing. All these parts have unique criteria that may change during any stage of a development cycle. And every time new criteria are added to the initial requirements, timelines change.В
- Dealing with unforeseen issuesВ
No one has 100% protection from unforeseen events. With software development, these issues can include overall performance, changes in the environment, architectural imperfections, availability of resources, and so on.
- Increasing the size of tasksВ
The ability to accurately predict the time and delivery of tasks are typically proportional to its size. In other words, the larger the job, the more unreliable the calculation. The size of tasks can also change during the development lifecycle, which can interfere with initial timelines.
- Availability of workers
No one can foresee when someone will have an emergency or get sick. When key workers in a development team have to take some time off, initial timelines may change.В
Why time estimation for software development is so important
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Estimating time for development projects is beneficial for everyone involved. Stakeholders can better visualize the whole scope of work and accurately plan the launch date. Good time estimation also leads to improved management of uncertainty and enhanced transparency in the whole development process. This positively impacts teamwork and the overall quality of work. In turn, these aspects can help to avoid turnarounds at later stages and missed deadlines that can lead to overspent budgets.В
How to estimate software development time
When it comes to setting accurate estimates, your best bet is to learn from experience. However, if you’re new to software development or working with a completely different project, you won’t have this option. Here are some key tips for making better estimates:
- Determine the sizeВ
The size of a project includes its scope, complexity, and risks. Let’s consider an analogy: Think about whether you’re building the Great Wall of China or the Eiffel Tower. The Eiffel tower is a large and complex structure, while the Great Wall is a more simple, but long structure spanning many miles. While both would be big projects, their scope, complexity, risks and, therefore, size is different. So, when discussing the total size and total duration of a project, you have to consider different ranges to mitigate uncertainty and unknowns.
- Set ballpark estimates
Before you get into a very detailed time estimation, it can be useful to make a general prediction of a project’s duration. This can help to form expectations. Ballpark estimates can be made based on previous experience with similar projects or industry benchmarks.
- Get different perspectives
The more viewpoints on a project, the easier it will be to find possible challenges that may hinder accurate time estimation. Each perspective looks at the idea differently and this can offer a lot of interesting insights on when and how things need to be done.В
- В Create smaller milestones
Another very useful technique of estimating a timeline for a software project is to break down the project into smaller elements. This process brings more clarity to what specific features need to be developed.
- Control uncertainties
Probability is not used as a strategy for making predictions. Instead, it is useful for calculating the unpredictable. Teams should always prepare for unknown factors and set aside additional time to deal with them. It is a good strategy to double an estimation to plan for the unforeseen without running out of time.
Remember: Every project is differentВ
Even though a previous project team or a competitor has accurately predicted their ability to execute a project in a set amount of time, doesn’t mean the same technique will apply to your project. While previous projects can be used as a guide, it’s important to understand that time estimates are non-transferrable: Every team must do their own unique time estimating to ensure accuracy.
Models for estimating
There are many different models for estimating time. Sometimes, they are also used together. Here are three of the most popular models used by software development teams:В В В
- Shared estimatesВ
Estimates should not be carried out in isolation. They must be performed collaboratively by the whole team. This avoids issues of not considering all aspects of the work involved to complete certain tasks and ultimately, the whole project.В
- Analogous estimatesВ
This estimation technique is often referred to as top-down estimating. It involves using experience or historical data from similar previous projects by applying observed costs, duration or resource requirements to a current project or parts of a project.
- Planning pokerВ
This technique combines expert opinions, analogy and team collaboration into a single reliable process. Planning poker brings together several experts who are best suited to build an estimate based on experience, lively dialogue and good justification.
Final thoughtsВ
Software development projects often overextend their time estimations, which results in enlarged budgets, lost revenue and missed market opportunities. To avoid these undesirable outcomes, it’s crucial to have a structured approach to evaluating a project’s duration. The above techniques can be used as a guide to building trust for everyone involved and ultimately, building confidence in deciding how to proceed.
