Everything You Need to Know About Schedule Performance Index in Construction

If you work in the construction field, you know that there are many terms and equations you can use that will allow you to determine how each project you are in charge of is doing. One of these equations is called the schedule performance index .

The schedule performance index, or SPI, will allow you to measure the progress of the project and will also help you determine whether the project will be completed on time, sooner or later.

The phrase schedule performance index is basically a fancy way of measuring how efficiently your project is running and is expressed as a ratio of earned value to planned value. Both amounts are always shown in dollar terms and you obviously want the amount earned to be higher than the planned amount.

The formula you want to use to determine the schedule performance index is SPI=EV/PV . SPI obviously means schedule performance index, while EV means earned value and PV means planned value .

The results obtained with this equation can be less than one, equal to one and greater than one. Depending on the outcome, you will be able to know whether your current project is on schedule or whether it will be completed later than planned or possibly even sooner.

The schedule performance index, or SPI, will allow you to measure the progress of the project and will also help you determine whether the project will be completed on time, sooner or later.

An SPI of less than one shows that your project is behind schedule, while an SPI of one shows that you are on track to deliver on time. The best case scenario, and the one everyone likes to see, is an SPI greater than one.

It's in these cases that you can congratulate yourself for keeping things on track because you're ahead of the game at the moment.

Knowing the schedule performance index at any point during current projects can be very helpful to you and those you work with. However, you can't just pull this figure out of the hat whenever you need to. Instead, you need to determine your schedule well in advance and know the numbers you're working with at each step of the process. This isn't an easy thing to do, but you'll be grateful you took the time to figure it all out when it saves you in the end.

The first thing you should do is divide your entire project into tasks and then assign a start and end date to each task, as well as a budget. This information is called the schedule baseline and will provide the information you need to track.

Next, you need to determine what the planned value, also known as the budgeted cost of scheduled work, is for each of these tasks. To do this, you need to multiply the amount of work that must be completed for each task by the budget for that task.

Your earned value, or the budgeted cost of work performed, is the amount of work for a specific task completed multiplied by the budget for that task. You will then have the numbers needed to determine your schedule's performance index!

Planned value = amount of work that should be completed for each task * task budget.
Earned value = amount of work for the task completed * task budget.

Knowing this number will allow you to make adjustments to your workflow and the amount of work that is completed each day, especially if you notice that you are running a lot behind.

If you are really having trouble finding time to determine the schedule performance index when you need it, you can easily determine the schedule variance. You will still need earned value and planned value, but for schedule variance, all you need to do is subtract planned value from earned value to see where you are in the project. This is much easier to do when you're in the middle of a construction site and have just a few seconds to determine where you are in the scope of an entire project.

A schedule variance of zero will show that your project is on track to complete when it should, while a number greater than zero will show that you are currently ahead of schedule.

Both may be helpful to you, but it's important to note that they are only giving you an idea of ​​where you stand in terms of the project. There are many variables that can change the outcome of the work being completed, as well as whether you are actually ahead, behind, or on schedule.

You should also be aware that your schedule performance index will work hand in hand with your cost performance index. While your schedule performance index shows how efficient you are with your project compared to your plans, your cost performance index will show how efficient you are being with the money you are spending to complete the work.

To determine your cost performance index, you will need to divide the earned value by the actual cost of the project to date. If your cost performance index is less than one, you have gone over budget and will earn less than anticipated on your current project. However, if your cost performance index is greater than one, you are under budget and will earn more than you thought when the project is completed.

Of course, you may find that your cost performance index equals one, which means you are on budget and earning what you planned. However, this scenario rarely happens, so you probably won't see it very often during your time in the field.

As you can see, these two ratios go together because you need both to successfully complete a project. After all, you may be way ahead of schedule according to your schedule performance index, but if you are spending more than you should and your cost performance index is too low, then you won't be earning what you should for the work you did. . they are doing.

You will need to determine at least the schedule performance index for each project you undertake because it may be the only way you will know where you are on the planned schedule. However, performing the calculations for both indices will allow you to see if your project will be a success or if you need to start making changes to future projects to avoid the same mistakes and problems in the future.

After all, there are no guarantees in this line of work, so every little help you can get, even if the help itself isn't guaranteed, is better than nothing! So, determine your schedule performance index right now, as well as your cost performance index, and see how your current project is aligning with all the ones you've completed in the past.