"Can't Rather than Don't" Makes Injuries Impossible
The "can't rather than don't" principle emphasizes using engineering controls to make safety incidents physically impossible, rather than relying on administrative controls that depend on worker vigilance.
- By William A. Levinson
- Jul 16, 2024
Henry Ford was well ahead of his contemporaries in terms of workplace safety, and the principles he used are still applicable today. Among these is what are now called “engineering controls” which make safety incidents physically impossible, as opposed to “administrative controls” that rely on worker vigilance and compliance. The problem with administrative controls is that one has to do the job wrong only once to suffer a lost work time injury or even worse. The best way to understand this principle is with a simple example.
In his 1920 article "How Henry Ford Saves Men and Money," Louis Resnick reported, "Even the simple little sewing machine—of which there are 150 in one department—did not escape the watchful eyes of the safety department. Every now and then, the needle of one of these high-speed machines would run through an operator's finger. Sometimes the needle would break after perforating a finger, and a minor operation would become necessary. When such accidents began to occur at the rate of three and four a day, the safety department looked into the matter and devised a little 75-cent guard which makes it impossible for the operator to get his finger in the way of the needle."
The administrative control—which consisted effectively of telling machine operators to not put their fingers under the sewing needle—was clearly not adequate to prevent three or four puncture wounds a day. These were even more dangerous in 1920 because neither antibiotics nor the tetanus vaccine had been invented. This engineering control made it impossible to put a finger under the needle because the guard is between the worker's index finger and the needle, but the fabric fits underneath the guard.
In his 1931 book Ford: Men and Methods, Edwin P. Norwood wrote that warning signs that admonished people to be careful "find their chief value as cumulative evidence for the defendant in lawsuits" and are of "scant preventive value in shops. … In so far as is practicable, it is not a case of 'Don't' but the installation of devices that stand for 'Can't.'" Instead of reminding sewing machine operators to not put their fingers under moving needles, the installation of the guard in question made it impossible to do so.
To this Norwood added that, if a safety incident did occur, what is now called corrective and preventive action (CAPA) was taken to ensure that it never happened again. This did not, of course, consist of retraining those involved or telling people to "be careful," but rather the application of engineering controls to make the problem impossible. Today, if a worker files a near-miss report, or what Japan calls a hiyari hatto ("experience of almost accident situation"), the near-miss would be treated as if the incident had actually occurred and corrective and preventive action would be taken to preclude it. Similar activities will also be evaluated to determine whether they also would benefit from the actions taken.