It has been my experience that very few companies use their SOPs to control outcomes. When they are available they are not self-checking and do not promote good practice. They offer little practical assistance to the user. Typically they are glanced over when operators and maintainers start a new job and then thrown to the back of the shelf to never be seen again. That is a pity because they are one of the most powerful learning tools ever developed. At least they could be if their supervisors and managers knew what could be done with an SOP.