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February 7, 2024

| 5 min read

Making sense of maintenance metrics: Scheduled maintenance critical percent

Welcome to our series of blog posts about maintenance metrics. This post outlines everything you need to know about scheduled maintenance critical percent (SMCP), from defining scheduled maintenance (opens in new tab), to exploring why SMCP is important, how to measure it, and how to use it. Discover even more about maintenance metrics by reading our series (opens in new tab).

What is scheduled maintenance?

Maintenance tasks come in all shapes and sizes, from the hurried repairs of reactive maintenance (opens in new tab) to the methodical ebb and flow of condition-based maintenance (opens in new tab). Regardless of the task, if it’s put in the calendar, given a deadline, and assigned to a technician, it’s scheduled maintenance.

Scheduled maintenance is any work that is arranged to be done ahead of time, whether that’s a day or a whole year in advance. Scheduled maintenance often takes the form of a recurring or preventive maintenance (opens in new tab) task, like lubricating bearings every 30 days. It can also be a one-time, pro-active or reactive task, such as replacing a rusted or broken fan. Any sort of maintenance task stamped with a timeline can be considered scheduled maintenance, including inspections, adjustments, regular service, and planned shutdowns. Scheduled maintenance is a lot of things, but it’s not planned maintenance. Although they mean the same thing, they are very different.

Calculating SMCP allows you to organize overdue PMs and decide which tasks should be prioritized…It does this by quantifying the impact of the task and the risk associated with delaying it.

Planned maintenance vs scheduled maintenance

Planned maintenance anticipates work and creates a process for completing it. It’s the act of taking a task and establishing how it’s going to be done, from start to finish. Maintenance is planned if there is a plan to address a situation, whether it’s running a lightbulb to failure or lubricating a motor bi-weekly.

On the other hand, scheduled maintenance is deciding when a task should be completed and who should complete it. Scheduled maintenance is just one step in the planned maintenance process. A task might be identified, such as the need to clean a filter, but it only becomes scheduled maintenance when it’s given a timeline for completion and assigned to a technician.

What is scheduled maintenance critical percent (SMCP)?

Everyone knows the feeling of getting home from a long day at work only to be greeted by dishes in the sink, a lawn that needs mowing, an overflowing laundry basket, and more. So many to-dos, so little time.

This probably feels familiar if you work in maintenance. It’s not that you ignore deadlines, but obstacles are inevitable. Unexpected breakdowns, production demands, and jobs that take longer than usual result in overdue maintenance. When you arrive at work in the morning and look at the backlog, it can be difficult to prioritize tasks. That’s where scheduled maintenance critical percent can help.

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Calculating SMCP allows you to organize recurring scheduled maintenance tasks (PMs) that are overdue and decide which tasks should be prioritized. It can also be used to communicate the value of maintenance to others within an organization and help balance production with repairs or inspections. It does this by quantifying the impact of the task and the risk associated with delaying it.

Calculating SMCP

The calculation for SMCP measures how late a recurring maintenance task is in relation to how often it should be occurring. Tasks with a higher percentage should be addressed before those with a lower percentage.

To calculate SMCP, start by adding the number of days a PM is late and the number of days in the PM cycle. Divide the result by the number of days in the PM cycle. Multiply this number by 100.

Scheduled maintenance critical percent = (Number of days a task is late + Length of PM cycle in days) ÷ Length of PM cycle in days x 100

Here’s an example of the formula in action: You’re supposed to lubricate the bearings on an asset every 30 days, but you’re three days behind on that task. You’re also supposed to swap out the motor on the same piece of equipment every 90 days. That work order is five days late. You only have time to complete one of these tasks today. SMCP helps you choose the most critical one:

PM #1 (Lubricating the bearings):

(3+30)  ÷


× 100%

= 110%

PM #2 (Replacing the motor):

(5+90)  ÷


× 100%

= 105%

After doing the math, it’s clear you should be lubricating the bearing before replacing the motor.

Discover everything you need to know about popular maintenance metrics and how to use them (opens in new tab)

How to improve your maintenance operation with SMCP

Being behind on your maintenance can drag down the facility’s production schedule and its budget along with it. SMCP acts as a guide, steering you clear of these risks, helping you use resources more efficiently, and leading you to a long-term solution for overdue maintenance. Below are three key steps to take to improve your maintenance operation with SMCP:

Every time a maintenance task is delayed, you’re placing a bet that the asset won’t break down in the meantime. This wager gets riskier as PM becomes more critical. You’re going to lose a lot of these bets if you’re not paying attention.

1. Targeting the root cause of the backlog

Tracking SMCP can help you determine why a particular task is constantly behind schedule so you can deal with the root cause. You may already know that a certain job is always overdue, but you might not know what sort of risk this is posing to your operation. By measuring SMCP, you can see which chronically late task is most critical. You can then investigate why. For example, you may find that a PM is always overdue because the necessary parts are never on hand. You can take steps to rectify this problem, like reassessing inventory purchasing processes.

2. Reducing unplanned downtime with better planning

Every time a maintenance task is delayed, you’re placing a bet that the asset won’t break down in the meantime. This wager gets riskier as PM becomes more critical. You’re going to lose a lot of these bets if you’re not paying attention. Calculating SMCP helps you make smarter decisions instead of gambling with asset health. It highlights which overdue tasks are too risky to let slide anymore so you can address them immediately. For example, prioritizing the task ahead of others or putting more than one technician onto a job.

3. Improving your health and safety process

There are all sorts of reasons that maintenance backlog can cause health and safety issues at your facility. Rushing from one job to another can mean forgetting key steps, which can be dangerous. Going past a deadline can also clash with compliance guidelines. SMCP allows you to prioritize the most important jobs so you can allocate proper time and resources to work. This helps cut down on hurried maintenance. It also keeps urgent health and safety tasks on the radar, so they don’t fall through the cracks and lead to failed audits or production issues.

Your business and SMCP

SMCP is a key component of scheduled maintenance as it allows your maintenance operation to be more efficient. There will always be work that is overdue, but SMCP allows you direct resources to the tasks that matter most, so being late isn’t a death sentence for your facility. It keeps risk at a minimum and acts as another tool for making data-driven decisions to improve and fine-tune your maintenance operation.

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