Accident prone

 Everyone makes mistakes. Martyn Brown looks at common error traps and how, through the ‘human performance equaliser’, they can be avoided. 

Human performance has come to the fore over the last few years. In 2013, there were major train crashes in Spain and New York, and a plane crash in San Francisco. In Spain, the train went round a bend too quickly¹, in New York, the driver had reportedly fallen asleep² and in San Francisco, it was the captain’s first landing at an airport and was allegedly receiving instructions from the co-pilot.³

Some people think such occurrences are just down to bad luck or technical failures. However, everyone makes mistakes. Most are quite minor and inconsequential, but a few will lead to a major loss or accident. In a critical task the magnitude of the error does not have to be large for a dramatic outcome. It could be as simple as saying ‘yes’ instead of ‘no’ during a two-person operation. It is worth remembering that human performance does not only relate to the safety aspects of our work. 

Experts in the field of human performance have asked why our species are prone to mistakes. One possible answer is that we fall in to ‘error traps’:⁴

In the 1980s, I had an audio system with a graphic equaliser on it, which displayed the output levels for a range of frequencies in bar graph form. Allocated to each band of frequencies was a slider control allowing the user to alter the tone of the music being produced. It was recommended by the manufacturer of the unit to set the graphic equaliser to produce a certain pattern for each type of music.

My background is in engineering and safety, and these subjects tend to merge when problem solving. This has led me to consider the graphic equaliser as a device to assist with changing adverse human performance. 

Each human performance ‘error trap’ is allocated two bars on a histogram, giving a total of twelve categories with two coloured bars each. This makes it possible to sub-divide each category into major (very significant, red) and minor (notable, blue) occurrences for a particular error trap.

All of us use some form of instrumentation during our daily lives to monitor equipment we use.

When a car displays its engine coolant temperature, a sensor buried deep in the engine measures that parameter and presents it to an indicator for display to the driver.

In the human performance equaliser (figure 1) the information is collected from the workforce. A form is sent out to work groups periodically at the site location – perhaps at the team brief at the end of the week. The leader of the group discusses the previous week’s work, noting human performance errors that have occurred.

 Someone might identify that they had to wait for 30 minutes for spares to complete a non-critical task – this would be recorded as a minor in the time pressure ‘error trap’.

Someone else might identify that in the closing minutes of the working day a critical task was completed with seconds to spare – this would be recorded as a major time pressure ‘error trap’.

At this stage, each group’s response should show a greater number of ‘minor error traps’ being encountered rather than the ‘major’ variety. Incidentally, if the reverse has genuinely happened with results showing more ‘major error traps’ than ‘minor’ – it is likely your business is in crisis.

Once each work group has submitted a response the results need to be compiled to create a bar graph of the whole site/location variant. When the equaliser is read, it will be clear that some errors have higher numerical values than others. It is also possible that those showing a high ‘major’ value will also show a corresponding higher level of ‘minors’. This should be taken as a warning that it is only a matter of time before a further ‘major’ error happens.

If the work groups have reported that time pressure is being encountered routinely (as a ‘minor’), then it would be no surprise if it subsequently featured in an accident or some other loss.

Obviously more peaks equate to more human performance problems but at least it will be possible to isolate the highest category in the first instance. Once each peak has been reduced effort can be concentrated on further reductions. A desirable position is to have very low levels across the whole of the human performance equaliser.

The raw data used in human performance pie charts is obtained from accident and event investigations. It is essential to probe into any event so the causal factors can be understood. During investigation the salient facts are often open to interpretation and it is possible that the conclusion reached is not correct.

An important part of health and safety is to carry out accident and event investigations. It is possible the conclusions arrived at are incorrect as the evidence for understanding the casual factors has been lost. An advantage of the human performance equaliser is that responses used to formulate it are upstream of events happening. It is also easy to see different traps for a variety of work groups. Every team including leaders would be expected to complete a return for collation. The error trap complacency is just as relevant to a manager as it is to the lowest grade person within an organisation, and perhaps even more so.

Readers might think that looking at and trying to alter poor human performance is a bit over the top. No matter what activity occurs, mistakes will always be made. Some of the best howlers can be seen in professional sport – a footballer misses an open goal, an athlete trips over, or a cricketer drops an easy catch.

The cost of setting up and running the human performance equaliser is negligible when compared to the possible benefits from it. There is no human performance mistake that cannot be rectified and mitigated by deploying counter measures previously identified. Making small, precise changes to a problem must be the definition of good safety management.

The human performance equaliser allows first-line management to ask about tasks being carried out in a standardised format. If a job has gone wrong, what caused the problem will be arrived at sooner because the answer will be which ‘error traps’ were encountered.

If an event in your organisation is significant enough to reach the media, you can be sure that it will be fully analysed. More than a hundred years ago commentators of the day wanted to know who was responsible for the loss of over 1,500 lives on the Titanic⁶. Incidentally, that question is still being asked today.