Ways to Write a Procedure
The typical way of writing a procedure is based on text. Here the procedure needs to be clearly written as an SOP is an instructional
document. Therefore, instructions must be written in the form of 'do this' or 'do that'. The text needs to consist of short
sentences that are written in simple, clear and directive language. Long and complex sentences that could be misunderstood
should not be used.
The effective use of white space is important for the impact on the reader and to clearly separate each individual instruction.
Rather than save paper and run all the text into large paragraphs, the text needs to be spread out to separate individual
instructions that make up the procedure. There will therefore be empty lines between each instruction. Some companies number
each instruction line and others don't, it is an organizational issue that probably goes back to when the quality system was
Let us look at instructions that could be in a written procedure for a laboratory. In Table 2 we have sample preparation instructions.
They are written in a clear simple style: do this or do that. However, look at Table 2 to see the differences in the use of
white space. In both columns are the same instructions for the sample preparation of samples for metals analysis by atomic
absorption. The instructions in the left hand column are all together and it is difficult to read or follow the procedure
in the laboratory. This series of instructions is what you would see in a scientific publication of a method but, in my view,
is not appropriate for a laboratory procedure.
In the right hand column of Table 2 are the same instructions but they are broken up into a series of bullet points to illustrate
the effective use of white space. The individual instructions can be easily followed and is how written procedures for either
analytical methods or work in the laboratory could be set out as.
Table 3: Procedure written using a process flow diagram with a process description.
Is everything good? No. Look in Table 2 at column 2 and the fourth bullet point. Here it states either digest the same for
110 °C until it goes brown (all cooking is just good chemistry!) or if you are lazy and want to go home early then leave the
samples at 40 °C overnight. Why the two options? Has the method been validated to cope with either approach? The instructions
for this step should be a little clearer in my view.
Can we make the procedure any better? Yes, by the use of process flow diagrams, an example of which is shown in Table 3. The
left hand column shows a process flow diagram of the procedure with each stage of the process shown as a box in the process
flow. The same text from Table 2 has been inserted in the right hand column without the bullet points and positioned next
to the appropriate process flow activity to add detail to the process flow. So this version of the procedure has a picture
to give the overview and the text to provide the detail.
We can develop this version of the procedure further by adding another column called 'responsibilities' on the right, to define
who does each step and where the hand over from one person to the next can be described as well.
How Long Should a Procedure Be?
This is never an easy question to answer but as short as possible is the best answer I can give. If necessary, have an overview
procedure or guideline and then break a process down into a number of smaller ones that will be read and used, rather than
filed and forgotten. My ideal SOP length would be in the region of 3–5 pages including diagrams, the shorter the better providing
that quality is not impacted.
How Do I Know You Followed the SOP?
In some quality systems there is the need to provide evidence that the procedure has been followed. In Chapter 4 of EU GMP
(1) on Documentation there is the requirement for instructions (to perform a task, e.g., SOP) and records which provide evidence
of various actions taken to demonstrate compliance with instructions. So records are the result of procedures being followed.
For an analytical procedure this is relatively easy as it's the sample preparation and analysis records that can be on paper
or in electronic format that demonstrate that the procedure was followed. For other procedures, the author needs to think
what evidence is generated by the procedure to provide evidence of compliance.
Training: Read and Understand or Assess Competence?
A classic method of training is the read and understand, where the procedure is distributed, either in paper or electronically,
to the analytical scientists who are going to use the procedure. Each person reads the procedure and then self-certifies that
that they have read and understood the procedure. Is this acceptable? It depends. If it is a new analytical procedure, then
probably not — you will want to have a better way to assess if an individual can perform the method and get acceptable results.
If it is an update of an existing method with minor modifications then 'read and understand' is usually acceptable. However,
the training world is moving from a 'read and understand' world to demonstrating an understanding or competence depending
on the nature of the procedure involved,
In this article we have looked at writing procedures which demonstrate how to perform an activity in a laboratory. Simple
sentences with specific directions are needed with a good use of white space to aid readability. Diagrams will help understanding
and roles and responsibilities need to be defined within the procedure.
(1) Principle of Chapter 4 on Documentation, EU Good Manufacturing Practice, 2011
"Questions of Quality" editor Bob McDowall is Principal at McDowall Consulting, Bromley, Kent, UK. He is also a member of LCGC Europe's Editorial Advisory Board. Direct correspondence about this column should be addressed to "Questions of Quality", LCGC Europe, 4A Bridgegate Pavilion, Chester Business Park, Wrexham Road, Chester, CH4 9QH, UK or e-mail the editor Alasdair Matheson