Standard Work Instructions and Standard Operating Procedures: What's the Difference?

Take a walk through any manufacturing shop floor and you'll notice carefully crafted documents that help workers do their job. Standard operating procedures and standard work instructions are key to success in manufacturing. They improve through document reviews, audits, a disciplined problem-solving process and, most importantly, input from the people who perform the tasks. The current documentation should be the starting point for every improvement. Always improve existing documentation before creating a new document. Volume does not equal continuous improvement. Many people think that operating procedures and work instructions are interchangeable terms, but they are not.

What are standard work instructions?

Standardised Work Instructions (SWI) are instructions designed to make your manufacturing processes consistent, timely and repeatable. They are often posted near the operator's workstation. Team leaders and managers should then follow up on whether operators use the instruction and are able to follow it – often the hardest part of the whole process.

It takes time and effort to produce SWI. They should state the best known steps to perform a process. Standard work instructions are a logical outcome of other process improvement initiatives, and they are useful in later improvement projects too. Without SWI, operators and their supervisors must rely on collective memory to keep performing a process the best way. SWI do not replace initial training, but they reinforce what was learned. An experienced operator may not need to look at the instruction every day. Posted instructions also help the supervisor, who can quickly see differences between the operator's actions and the standard.

It is important to review and update the SWI for each task regularly. An organisation using the kaizen approach of continuous improvement will keep finding better ways of doing tasks, and updating the SWI is how those improvements stick. In practice, instructions start to age the moment they are created, so they need continuous improvement.

What are standard operating procedures?

Standard Operating Procedures (SOP) are written, step-by-step descriptions of how to perform a routine activity. An SOP describes the activities needed to complete a process in line with industry regulations, legal requirements or simply your own standards for running the business. Employees should follow them the same way every time so that the business stays consistent. SOPs help maintain safety and efficiency in production, operations, training, sales, finance and other departments.

A standard operating procedure should never be hard to read or vaguely worded. It should be brief, easy to understand, and contain action steps that are simple to follow. A good SOP clearly outlines the steps and informs the employee of any safety concerns.

SOPs are an integral part of quality control and risk reduction. From aerospace manufacturing to pharmaceutical production, good SOPs are more than red tape. They define who does what, when and where. If SOPs are poorly written or implemented, the consequences can be serious. Standard operating procedures should be the basis for training new employees, and they should be reviewed regularly so they stay relevant to how the organisation actually works.

Difference between SWI and SOP

SOPs are higher-level documents that tell employees which actions to take in a range of circumstances; work instructions describe those actions in detail. Work instructions aren't necessarily long. They should be as clear and concise as possible, and narrowed to an individual task within an SOP.

Many companies organise their documentation in layers:

• Standard operating procedures are the upper layer. They describe which actions to take in a range of circumstances.
• Standard work instructions are the lowest layer. They describe the work to be performed at the lowest level of detail. As the name implies, they are instructions for a specific piece of work. Some are less than one page – just a short list of steps.

This hierarchy is a common convention, not a requirement. ISO 9001 asks you to maintain the documented information your processes need to run as planned, and to control it. It does not prescribe how many layers you have or what you call them.

	Standard operating procedure (SOP)	Standard work instruction (SWI)
Purpose	Defines a process: what happens, who is responsible, under which conditions	Shows exactly how to perform one task
Scope	A whole process, often across roles or departments	One task at one workstation or machine
Audience	Supervisors, engineers, quality, auditors, everyone involved in the process	The operator doing the task
Level of detail	Medium: steps, responsibilities, references to other documents	High: each action, tool, setting, check and safety point
Who writes it	Process owner or quality, approved by management	Process or manufacturing engineer with experienced operators
Example	Procedure for receiving and inspecting incoming material	How to measure and record the bore diameter on part 4711

Where REWO fits

REWO Guides are built for the lowest layer: visual, step-by-step work instructions from video, images and text, with approval and version history, opened at the workstation by QR code or from your MES.

Read next: Standard work instructions and lean manufacturing · Work instructions vs job aids · REWO Guides