By Jane Sleeth
These flawed decisions are based on a misunderstanding of cause-and-effect reasoning, a lack of understanding of epidemiological analysis of work injury statistics, and the unwillingness of politicians and employers to bring these flaws to the attention of policy makers at the boards.
First, an explanation of cause-and-effect: When we ask the question “why”, we wonder about the causes of an event. Every time we ask, “what would happen if…” we are wondering about the effect.
Psychologists try to explore the causes of their patient’s behavior; car mechanics find the causes of malfunctioning engines; and physicians try to find the causes of their patients’ symptoms.
Following are some of the typical errors made when cause-and-effect relationships are established around work-related musculoskeletal injuries.
Post hoc refers to a logical error when we assume that because one event comes after another, the first is the cause of the second.
Oversimplifying multiple causes is an error that occurs when we pinpoint one thing as a cause when, in fact, there are many causes. For example, if an adjudicator states an MSI was caused by the job demands of an electrician’s work, they are in fact stating there is only one cause for the MSI. And yet gold standard research readily available to the boards clearly shows that MSI can be caused by a number of factors such as gender, underlying illness, unhealthy lifestyle, socioeconomic factors and cultural factors.
Mistaking a correlation for a cause results from an assumption that when two things occur together, one had to have caused the other. A well-known medical example is the long-held assumption that high cholesterol causes heart disease because people with heart disease often have high cholesterol. An assumption on the correlation between cholesterol and heart disease indicates that one caused the other. However, recent research reveals that medical practitioners’ assumption about this relationship is false. In fact, both high cholesterol and heart disease may be caused by a third factor: high levels of certain amino acids.
In the case of MSIs, compensation boards are making similar flawed assumptions. For example, if an employee presents with pain in his physicians’ office and the employee states that the job had caused the injury, the board assumes that the workplace is the cause.
Research we conducted at OPC Inc. reveals many job demands may well aggravate an underlying MSI, but more often than not, the job demands are not the causative factor.
Adjudicators, decision makers and physicians therefore need to qualify their assertions. In the case of MSI, it is truly impossible to prove that one event in the workplace or events over time caused the injury.
Decision makers are rarely aware of the employees’ workplace environment and are often not qualified ergonomists to effectively analyze the workplace for hazards and risks. So without access to substantial proof, adjudicators, workplace decision makers and physicians cannot determine that a particular workplace is the cause of or at least correlated with an MSI.
There are four basic organizational patterns that need to be explored when performing causal analysis. The compensation boards and physicians need to go back to school to learn how this reasoning occurs:
•Multiple Causes, Single Effect – For example, mechanical low back pain can arise from a number of causes both work-and non-work-related. The result for many employees is “run of the mill” mechanical low back pain.
•Single Cause, Multiple Effects – Exposure to vibration may be the single cause, but the effects include loss of hearing, loss of sensation, altered reflexes, and visual disturbances.
•Multiple Causes, Multiple Effects – Employees exposed to manual materials handling, vibration and shift work tend to show a pattern of similar multiple effects such as mechanical low back pain, fatigue and human error.
•Alternating Causes/Effects in a Chain – MSIs, such as carpal tunnel syndrome, may result form underlying medical conditions such as diabetes or obesity, with work-related additional factors being vibration, repetition or high force mechanical loads at the wrist.
Respected journal, Occupational & Environment Medicine 2008 recently reported on a new research entitled, How Common is RSI (MSIs). The objective of this large study was to show the flaws in using the European Labour Force Survey Statistics as evidence for the scale of occupational MSIs.
The fact that European governments (and by extension provincial governments in Canada who rely on similar statistics) use these statistics to determine occupational health and prevention strategies reveals how decision makers can base their assumptions on non-valid data.
Interestingly, the U.K. and the European Commission are seeking a 20 and 25 per cent reduction of “work-related RSI (MSIs) between 2007 and 2012 based on these surveys. For Ontario employers this should sound familiar as the Ministry of Labour’s Strains and Sprains Campaign aimed for a 20 per cent reduction in MSIs by the end of 2008.
MSI reduction goals by labour ministries and compensation boards should be tempered by findings from this and other related studies that found, “counting people with arm pain which they believe to be work-related can overestimate the number of cases attributable to work substantially. Furthermore, the degree of overestimation varied by age and mental health status…this calls into question the use of the Labour Force statistical reports to quantify trends in occupational illness nationally and internationally. It also has implications for the validity of reporting schemes for occupational disease more widely”.
In short, using these types of surveys and statistical reports provided by employers to the compensation boards and ministries of labour is a flawed approach in trying to determine the cause-and-effect relationship for MSIs in particular. All stakeholders, particularly employers who pay premiums to the boards, need to question the validity of these studies and suggest a better way to determine cause-and-effect relationships.
Without this dialogue, the adjudicators, family physicians and health care workers who work with employees will make the assumption on your behalf – and employers will continue to pay increasing premiums and penalties for this.
Jane Sleeth is the owner and senior consultant with Optimal Performance Consultants, an ergonomic, accessibility and disability prevention firm located in Toronto, which just celebrated its 25th year. Sleeth and her team of consultants can be reached at firstname.lastname@example.org