An s-curve is a mathematical graph used for project management to track the progress and data of a project — such as man-hours, costs, cash flow, or another resource — plotted against time (days, weeks, months, etc.). This visualization is called an s-curve because the graph often looks similar to a loose letter S.
The value of an s-curve is its effectiveness in tracking important real-time cumulative data that helps project managers keep projects on schedule and within budget. It may also help them evaluate individual team members’ performance and forecast cash flow. In short, s-curves are a valuable way to ensure your project will meet its goal and requirements, while helping you communicate progress to stakeholders.
Managing Projects with S-Curves
S-curves are helpful when you want to visualize large amounts of data, generally tied to tracking progress and productivity. If you’re surprised that the graph looks like the letter S, consider the typical stages of a project and remember that an s-curve plots specific data against time.
In the early stages, project growth is slow because you’re just getting started. As time goes by and your team makes progress, you reach the inflection point, which is the middle part of the project and represents maximum performance. After this point, the project matures and productivity eventually winds down as you shift focus to other work.
There are multiple types of s-curves, including:
- Baseline s-curves
- Target s-curves
- Costs vs. time s-curves
- Value and percentage s-curves
- Man-hours vs. time s-curves
- Actual s-curves
Before a project starts, you create a schedule to plan out anticipated resource allocation and flow of tasks. This is your baseline schedule and the s-curve created from this schedule is a baseline s-curve, which shows anticipated progress. As the project progresses, you can revise your baseline schedule, whether you need to change scope, timeline, or task sequence.
Once you start working on a project, adjusting your baseline schedule is common. This adjusted schedule is the production schedule used to produce a target s-curve, representing a project’s ideal progress if everything unfolds as planned.
If your project manages to remain within budget and on time, the target s-curve will intersect with the baseline s-curve. However, it’s more common that the target s-curve ends up above and to the right of the baseline, as many projects come in late and over budget.
Costs vs. Time S-curves
This s-curve displays the total costs incurred from a project’s start to finish date, including hiring contractors and paying vendors. This data helps you calculate total project costs and predict cash flow.
Value and Percentage S-curves
When creating an s-curve, you choose the resource you want to track against time — whether it’s employee hours, cost, or something else. A value s-curve is one that measures the hours or money contributed to a project so far and what’s needed to complete the project. Percentage s-curves compare your actual resource use to what was planned, so you understand how successful or off-track a project is.
Man-hours vs. Time S-curves
A man-hours vs. time s-curve is helpful for labor-intensive work, showing the number of employee hours put into every phase of the project. Man-hours refers to the human time needed and the number of hours it takes to execute a task.
Throughout the duration of a project, it’s common to adjust your production schedule. Revisions include actual data from work you’ve completed, which can be used to generate an actual s-curve. Comparing your target s-curve to actual s-curve helps you understand how realistic your plan was and how productively your team has performed. For many projects, the actual s-curve is lower than the target s-curve because of delays or schedule changes, but the curves intersect at the end of the project.
S-Curve Use Cases
S-curves make it easy for project stakeholders to track progress and understand productivity. Analyzing these graphs can identify where you’re over- or underperforming compared to project goals and identify potential issues to resolve them quickly. They also help with project budget and profit forecasting, making it easy to monitor and predict costs and cash flow.
S-curves give project stakeholders a visual way to see the pace of your firm’s work, which phases will demand more resources, and when you need to add contractors to supplement your team. Because s-curves are easy to play with and adjust, you can always change the data to see how a different schedule, team size, or injection of resources would change the outcome of your project.
All project managers have wondered when the latest start date is to still finish on time or the fewest resources they can leverage to still complete work successfully. You create banana curves when you plot both possibilities of a data range. This helps you determine how a project will progress in either scenario, so you know what to expect based on the actual start date.
How to Make an S-Curve
Project management software significantly reduces the time it takes to make s-curves by granting you instant access to the data you need. With a platform like BQE CORE, real-time dashboards let you track and export the crucial project data you need to create these graphs, such as planned employee time, project expenses, milestones, and finish date.
Some of the s-curve-relevant reports you’ll find in CORE include:
- Planned value, which is the expected delivery value of work according to the original project plan.
- Earned value, which tells you how much you've billed so far against the contracted total you're supposed to bill. It represents the actual value of your firm’s billed time and expenses for a project based on the time and expense entries you log.
- Actual cost, which is the true total costs you accrue while completing work up until the project’s finish date.
As the project lifecycle goes on, CORE records data based on the actual resources used and cash flow produced, which you can use to compare to your baseline s-curve. Seeing where the target s-curve is vs. baseline s-curve will help your firm adjust to get projects back on track and plan more accurately in the future.
Project management tools from BQE
Your firm’s project planning must be precise because so many factors can affect your ability to finish projects before the deadline, without going over budget, and to make your firm successful in the long run. Monitoring your data using s-curves and project management software will help you keep an eye on expenses, cash flow, and employee time, so you foster long-term profitability.
S-curve data is just a minor piece of what project management software can do for your firm. CORE helps you plan and monitor projects and your team, with built-in expense reporting software and automatic billing software to keep you organized, efficient, and compliant. CORE also has more niche, industry-specific offerings, including legal billing software and project management software for engineers.