What is a Standard Operating Procedure (SOP)?
A standard operating procedure (SOP) is a controlled document that explains how to carry out recurring work consistently. A useful SOP procedure identifies the responsible role, the required steps, the decision criteria, and the expected result so the same operation procedure can be followed each time.
This guide explains why operational procedures matter, how an SOP process differs from a work instruction, and what to include in an SOP plan. Whether your organization calls it an SOP, a system operating procedure, or a standard operating process, the document should give the reader clear instructions without more detail than the task requires.
What Is a Standard Operating Procedure?
An SOP, or standard operating procedure, is a written method for controlling a recurring practice according to predetermined requirements so it produces a desired outcome. Consistency is the purpose: the organization defines the accepted way to perform important work, then trains and supports people to use it.
An important aspect of any quality system is working in accordance with clear-cut standard operating procedures. An SOP describes the regular recurring activities appropriate to quality operations. The goal is to carry out operations correctly and in the same manner whenever the defined conditions apply.
You may also see the phrases standard operation procedure, standard operation procedures, operational procedure, or system operating procedure. In this article, SOP means the controlled procedure used to direct recurring work. An SOP does not replace judgment, training, supervision, or the resources needed to complete the work safely and correctly.
Why Do We Need Procedures?
The Policies and Procedures Manual guide provides a broader method for organizing a complete manual. An individual SOP turns one recurring part of that system into controlled action.
Procedures translate policies, standards, and control requirements into repeatable action. They help an organization define roles and responsibilities, control measures, handoffs, records, and decision points. They are especially useful when an activity is Critical To Quality (CTQ), critical to safe operations, critical to security, or difficult to perform consistently from memory.
Common examples include good manufacturing practices (GMP), plant safety routines, financial controls to secure assets, and IT security measures. The appropriate document depends on the risk, the reader, the applicable requirement, and the amount of detail needed.
Some regulated activities specifically require written procedures. OSHA’s process safety management standard requires employers with covered processes to develop and implement written operating procedures with clear instructions for safe operation. This requirement applies to covered processes involving highly hazardous chemicals, not to every workplace.
In pharmaceutical manufacturing, 21 CFR 211.100 requires written production and process-control procedures to be drafted, reviewed, approved, followed, and documented. ISO 9001 addresses documented information and the planning, implementation, and control of processes as part of a quality management system. These examples show why the applicable rule or standard must be checked directly instead of assuming every framework requires the same SOP format.
Procedures Protect Processes
A procedure or work instruction can act as a control for identified risks that may create defects, injuries, security incidents, or nonconformances. The document alone cannot guarantee an outcome. Its job is to define the expected method and make deviations easier to identify, investigate, and correct.
If a step is CTQ, it is a strong candidate for an SOP standard operating procedure. The SOP process can specify the acceptable sequence, criteria, records, and escalation path that protect the larger business process from avoidable variation.
Procedures Protect Workers
Workers who follow an established procedure can see which actions management has approved and which controls apply to the task. A procedure can define safe steps and stopping points, but it must work with training, supervision, suitable equipment, and the regulations that apply to the job.
Procedures Protect Customers
Customers expect dependable product or service delivery based on accepted measures, not on one worker’s personal preferences or location. Standard operation procedures help reduce variation by defining the same controls, checks, and records for everyone who performs the work.
SOPs and Work Instructions
Some SOP procedures use a two-tiered system. The procedure gives a general view of the higher-level steps, responsibilities, controls, and decision points. A work instruction explains how to complete one task in more detail.
This separation keeps the procedure stable while work instructions can change when equipment, application software, organizational structure, or task details change. It also helps an experienced Subject Matter Expert (SME) move quickly through the operating process while giving a new worker the detailed support needed for a specific step.
| Document | Purpose | Level of Detail | Use It When |
|---|---|---|---|
| Policy | States a rule, principle, or management intent | Low | People need to understand what is required and why |
| SOP or procedure | Defines who does what, when, and to what standard | Medium | Recurring work needs consistent roles, controls, and outcomes |
| Work instruction | Explains exactly how to complete one task | High | A task needs screenshots, settings, measurements, or detailed steps |
How Do You Design an SOP?
The procedure design phase should describe who does what and when. An SOP characterizes relationships and control measures so workers can find themselves in the business process. It clarifies roles and responsibilities, different decision points, and the criteria needed to make a decision.
Before drafting, answer these four questions:
- Who does what? Name the responsible role rather than relying on a person’s name.
- What do they do? State the task, frequency, standard, and relevant criteria.
- What is the outcome? Identify the deliverable, record, measure, or objective result.
- Is the required action clear? Test whether a qualified reader can identify the next step and the decision criteria.
Write Steps That Move Forward
Begin each SOP step with an action verb. Keep each step distinct, make decision points clear, and show cause-and-effect relationships when they matter. The flow of a procedure should move forward over time. If a step needs extensive how-to detail, place that detail in a linked work instruction.
Use active voice construction where it improves clarity, and make cause-and-effect relationships clearly defined. State deliverables, measures, and objective results when they help the reader confirm that a step is finished.
Write for the People Who Use the Procedure
Analyze your audience and the information they need. Experienced workers may consult the procedure only for infrequent tasks, error conditions, or decision criteria. New workers may need a related work instruction, examples, annotations, and On-the-Job Training (OJT) checklists.
Organize related information together so readers can navigate from the general process to the specific detail they need. Use headings, lists, graphics, tables, and simple diagrams as visual anchors, but keep the essential control and decision information in text.
Think about who will be reading the procedure and define the types of information needed to meet your audience’s needs. Visually distinguish related material, keep related pieces of information together, and break long content into related groupings so readers can move from general guidance to specifics quickly.
Test the Procedure in the Field
A draft should be checked by the people who perform, supervise, and depend on the work. Walk through the steps, confirm that the sequence matches the real task, test exception paths, and verify that required records can be produced. Revise unclear language before approval and release.
How Do Process Maps Help You Write an SOP?
During the design phase, decide which tasks need process mapping. Lay out the steps currently used to complete the task, including handoffs, inputs, decisions, exception paths, and outputs. This creates an SOP process flow that can be tested before the writing becomes fixed.
Once the task has been mapped, test the map in the field to confirm that all necessary detail has been captured. Improve the sequence where practical, then convert the process map to an outline for the written procedure. Include the map or a simplified version when it helps readers understand high-level and detailed relationships.
Process mapping involves taking each step in the task and making the flow more efficient and easier to follow. Once you have finished mapping, convert the process map to an outline. Process maps, graphics, tables, and simple diagrams can provide a useful visual anchor and reference information for clarity.
A process map is not a substitute for the procedure. The map shows flow and relationships; the procedure defines responsibility, control criteria, records, and what to do when the work does not follow the normal path.
How Do You Write Work Instructions?
Work Instructions define the how-to information needed to complete a task mentioned inside a procedure. They are action-focused and may include a numbered list, a checklist, pictures of dials or switches, or computer screenshots with annotations. Label each visual so the user knows what to look for and what result to expect.
Work Instructions help fill in the blanks wherever information is needed to support processes, procedures, or templates. Pictures of dials, switches, or computer screen shots should include annotations that clarify the meaning and tell the user what to expect.
Work Instructions often focus on the person who is new to the task, while procedures may assume capability in the general area. Neither document replaces training. Structured OJT can demonstrate the correct method, while the controlled document gives workers a consistent reference after training.
The content for both procedures and work instructions should come from relevant SMEs and people who perform the work. Documents and the records they require may be examined when they fall within the scope of a quality, safety, financial, or regulatory audit, so the language should match the work the organization actually performs.
Standard Operating Procedure Checklist
Use this checklist to review a new or revised SOP before approval:
- Purpose and scope: State the outcome, trigger, boundaries, and activities covered.
- Responsible roles: Identify who performs, approves, receives, or monitors the work.
- Inputs and prerequisites: List the information, equipment, training, forms, or access needed.
- Sequence: Put the normal steps in a clear forward flow and begin steps with action verbs.
- Decision criteria: Explain how the reader chooses between paths and when to stop or escalate.
- Controls and records: Define required checks, approvals, evidence, and retained records.
- Exceptions: Explain what happens when information is missing, a control fails, or the result is outside tolerance.
- Related work instructions: Link detailed task instructions rather than overloading the SOP.
- Field test: Have a qualified user walk through the document and record unclear or missing steps.
- Approval and review: Assign an owner and review the SOP when the process, risk, equipment, system, or requirement changes.
For example, a purchase-approval SOP may identify the requester, budget owner, approval threshold, evidence required, decision criteria, and purchase record. A separate work instruction can show how to enter the approved request in a specific system. This keeps the standard operating process stable even when the software interface changes.
Frequently Asked Questions
What Is the Difference Between a Policy, Procedure, SOP, and Work Instruction?
A policy states a rule or management intent. A procedure or SOP defines who performs recurring work, in what sequence, and to what standard. A work instruction gives the detailed how-to steps for one task inside that procedure.
How Detailed Should an SOP Be?
An SOP should contain enough detail for a qualified reader to understand roles, sequence, controls, decisions, records, and exceptions. Put screen-level or equipment-level instructions in a separate work instruction when that detail would make the SOP difficult to maintain.
Who Should Write and Approve an SOP?
A relevant SME and people who perform the work should help draft and test the SOP. The process owner or designated authority should approve it according to the organization’s document-control rules.
When Should an SOP Be Reviewed?
Review an SOP when the process, risk, equipment, software, organization, or applicable requirement changes. Also use the organization’s scheduled review cycle to confirm that the document still matches current work.
Should an SOP Include a Process Map?
Include a process map when flow, handoffs, decisions, or exception paths are easier to understand visually. Keep the responsibilities, controls, records, and escalation instructions in accessible text as well.
Working from well-defined SOPs is an important part of a quality management system and a practical way to make recurring work easier to understand. You can use the checklist above with the SOP template guide, or download free policies and procedures samples to customize for your organization.
