Short Interval Control (SIC): How to Stay On Task and On Time

Takeaway: Short Interval Control is a powerful structure for removing variation and staying on task and on time.


If you have any processes or activities where variation is an issue, Short Interval Control can help. Short Interval Control uses structured process checks in short intervals to maintain control and ensure quality.

We often talk about averages in business. But customers don’t feel “averages,” they feel variation. We want to give our customers (both internal and external) the quality experience that is expected by them. We want to remove unwanted variation.

We must design processes that:

  1. Are reliable
  2. Are repeatable
  3. Are capable
  4. Flow

Reliable – We must develop processes that not only meet customer requirements, but that are reliable. We want robust processes. We want to avoid spending large amounts of effort and attention to maintain a set tolerance. We need to be running at the center of our specifications. We need to be always working to improve the stability of all processes. We want confidence we are maintaining process control and delivering quality on the first try.

We may have equipment that is repeatable and capable, but if it breaks down often, or is prone to jam ups, etc. it is not reliable.


Repeatable – Means our process is consistent in producing quality products and services. We know what to expect from the process. We know the process performance history and that it can maintain consistently good quality.

We may have processes that are capable of meeting quality standards and are reliable, yet they are not stable. They easily float out of the specification tolerance. The process needs constant babysitting.


Capable – Means we know our processes are capable of meeting customer requirements and demand. We are well within tolerances of set specifications and have good control of variation.

Lack of capability would mean the equipment or process was not able to meet the customer’s needed specifications. They will experience lots of variation.


Flow – When we know our processes are reliable, repeatable and capable. We can move through our value stream at a rate determined by customer demand.

This means we are running our processes and they are not running us. We have control. We have a robust operation that gives us a high level of confidence that we can meet our customer’s needs. We do not need to build access inventories and have created pull signals to increase flow.

We know we will encounter problems, but these will most likely be detected quickly and dealt with in an efficient manner. We have safeguards in place to alert us to issues and protect our value stream.


Establishing Short Interval Control

We need to know all process capabilities. Short intervals are created in the form of quality checks as required for process control.

The robustness of the process will determine how often these checks need to take place:

  • Every hour
  • Every two hours
  • Every four hours
  • Etc.


We do not want to overburden workers with excessive process checks. We are verifying quality control. We never want to pass a defect to the next downstream customer.

Simple charts can be created to capture the performance variation data.

Make your short interval control charts easy to use. Create a simple check sheet or form for capturing whatever is being monitored. Mobile devices are great for collecting and sharing this information.  

Graphs are great for driving behavior with this type of data. When graphs are set up with the upper and lower limits, the plotted dots placed as short interval control checks take on a visual form. These have instant meaning to anyone that sees them.

I have seen companies reduce waste and improve work just by implementing visual graphs. As workers updated the graph, it showed how they were performing against set targets, and all could see it. They became much more conscientious.


Quality Assurance is Everyone’s Responsibility

To establish good quality checks and ensure process control, we begin with operator checks at short intervals and expand the duration and level, working up through management.

As the operator maintains the short interval control charts, they are gathering and posting valuable information. This does little good if no one reviews it. We want to create set loops where all levels are involved in helping maintain quality. Check out this article on MCRS for information on this.


Short Interval Control Benefit

If we want any system followed that requires effort (like process checks), we need to see the benefits. Short interval control is one more thing a worker needs to do. Though it should not take up much time, it is still an extra activity.

Implemented correctly, SIC will alleviate stress on individuals and foster teamwork.


Here is the benefit to the worker:

We never want anyone dealing with a problem on their own. Short interval control begins with an employee recording the status of a critical process on a short interval control chart or graph.

As others see the chart, it should call them into action based on need. No longer will an employee face a problem alone. When problems arise, the cavalry should come in for assistance. They are not asking for help on their own; it is built into the system. No one likes asking for help. We need this as part of our standard work.

We don’t want management ever to see that a lone employee battled an issue for hours without proper aid and support.


Nektar Data Systems

We need to know where we are regarding critical business KPI’s. The best approach is to merge real-time data collection with technology that allows us to access it as useful information.

It was for this very reason that Nektar Data Systems was created. We needed better control of our data collection regarding our business asset utilization. Like many businesses, we needed to know how well our equipment was performing and track aspects of our business involving construction projects, contractor management, equipment and employee time use, etc.

This information is important to our customers and to us. Equipment downtime, re-work, and time setbacks create variation that negatively impacts lead time. (Lead time for a business is defined as; the time between when a business receives an order for a product or service, the business delivers that product or service, and then receives payment.)

Reliable data drives actions that create success. We must know we’re doing the right things when needed, not after the damage is done.

Review your key processes; are they reliable, repeatable, and capable; do you have flow? Let Nektar Data help you make the most of short interval control. Contact us today.