Tips for Writing an Effective SOP

A quick review of 21 CFR parts 210, 211, and 820 will find numerous references to written procedures. These written procedures have come to be referred to as Standard Operating Procedures, (or SOPs, as they’re more commonly known), and are a tool used in most every industry to help achieve uniform results. Creating a written procedure that everyone can follow takes the guesswork and uncertainty out of the process equation. Our experience has shown that a good written procedure will contain certain elements.



The purpose statement identifies the goal of the SOP. It answers the question of why the SOP is being written. For example, “The purpose of this Standard Operating Procedure (SOP) is to specify the processes used to manage SOPs. This includes the creation, training, review, modification, and archiving of SOPs.”


The Purpose statement needs to be detailed enough so that the intended user can recognize what the document covers, but not so lengthy that it sounds like a synopsis of War and Peace.



The scope of the SOP identifies who needs to follow the procedure and what the procedure covers. It should help the reader to identify what is (and what is not) covered in the procedure. For example, “This procedure applies to all internal documents and the personnel who write them. It does not apply to documents written for external distribution.” Often an SOP will state what is in scope without stating what is not in scope. However, don’t hesitate to declare what is out of scope. It is better to be clear than to leave room for interpretation. When writing an SOP, you may be perfectly clear about whom and what are included, but the reader may not have our expertise or range of vision. By spelling out clearly who and what are, and are not in scope, the risk of creating confusion is decreased. This allows everyone to have the same starting point.



List the roles that are needed for each task in the procedure. Include the responsibilities for each role. A list of roles and responsibilities allows the reader to quickly identify who is responsible for each task, including their role in the SOP’s implementation. If you find that you have a large number of roles listed here, you might want to narrow the scope and create several related SOPs to complete a large task. Don’t forget to include any role that management might have in the implementation of the procedure. Roles can then be assigned to qualified individuals, and a list that indicates who is assigned to each role can be posted for further clarification.


References / Related Document

All other SOPs, documents, or government publications that are directly referenced in the SOP must be listed in this section. Include any job aids or work instructions that might be used to execute the task in the procedure. If you have a Master Reference Document, you can list the title and any identifying numbers for the referenced documents. If not, you need to list the entire reference cited, using the standard reference format for publishing, or your local convention. Additionally, list other documents and sources that may not be referenced in this SOP, but would be helpful for the reader, should they need more information on performing this procedure.



You can use this section as a glossary to define any acronyms or abbreviations that are used in the procedure. Even if they are very familiar to you, they may not be to the reader. It can also be used as a dictionary to spell out any terms or phrases that may not be common knowledge to everyone. While your primary target audience will be the actual users who perform the tasks in the procedure, you need to write with any regulatory or governing bodies in mind. If your process is ever audited, a clearly defined SOP will help the auditor understand your procedure and not give them cause to investigate deeper.


General Information

If you need to give some background information, or list any warnings or precautions before performing a procedure, this section is the place to list them. Warnings and Cautions should be set out from the regular text by using bold, italics, underlining, or color (or combination).


Materials and Equipment

List all of the materials and equipment needed to complete the procedure. If the procedure is written to operate a specific piece of equipment, make sure the user guide for the machine is listed in the References section, and that users have been trained on operating the equipment prior to performing the procedure.



This section will include how to perform the task or process covered in the procedure. It is important to include enough detail to guide the user through the process, but not so much detail that the user is boxed in by the procedure. For example, “Access the internet” is appropriate. “Access the internet using a PC with IE10 as the default browser and the zoom level set at 75%” is not appropriate.


Here are some tips for writing the procedure:

  • Use numbers for steps and sub-steps that have to be performed in a specific sequence.
  • Use bullets for steps or items that can be performed in any order.
  • When there is more than one right way to perform a task, chose the one that is the most efficient and easiest to understand.
  • Keep the user in mind. You are most likely an experienced user if you are writing the procedure. There is a risk that as an experienced user, shortcuts have been discovered.
  • Solicit ideas from other users.
  • Test the processes with a new user. Their feedback can help you add details that are necessary, but that may not be obvious to you.
  • Include a flow diagram, if possible, to help interpret more complex procedures.


Remember, the SOP is a high-level view of the process. If your SOP is twenty pages in eight to ten point font, it is probably too detailed or complex.



Don’t just paraphrase the Purpose section, but give the reader a clear picture of what the procedure is trying to accomplish. Especially in a manufacturing setting, the Analysis section should describe the finished product, and outline the defect tolerances (if any), as well as what is considered an acceptable product.



In conjunction with the References section, use this space to list the forms or supporting documentation that are necessary to complete the procedure.


Summary of Changes / Revision History

Include a table that lists the version number of the SOP, the approval date, a description of the changes, and the author of each set of changes. This information is required by 21 CFR Part 820.40. The regulation also requires that an effective date for the changes be included somewhere in the document.
The Revision History table needs to be updated each time the procedure is updated and approved. Each approved revision should be a major version revision, taking the document from version 1.0 to 2.0.


Approval Signatures

Depending on the industry or the governing regulatory agency, the SOP will need various approval signatures. Some roles to consider are: Author, Reviewer, Management Approver, and Quality Reviewer/Approver. Under 21 CFR Part 211, the quality control unit is required to approve all procedures that may impact “the identity, strength, quality, and purity of the drug product.”
The signature page is usually on the cover or the back page. Spell out exactly the meaning of each signature, and include space for the signatory to print and sign their name. A place to enter the date the document was signed is also required.


Headers and Footers

Headers contain the company name or logo, the title of the SOP, and the document number. Footers contain the version number, page numbering in the form of Page x of y, and any confidentiality statement or indication (if necessary). Some companies place an issue date and the effective date of the procedure in the header or footer. The issue date is typically 7 to 14 days in advance of the effective date, to enable personnel to obtain adequate training.


Once the SOPs are written, don’t forget the next step—ensuring the right people are trained on the SOP.


John Steichen is Senior Compliance Advisor at Safis Solutions.
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