Occupational Injuries Decline
Do We Know Why? Copyright 2004

Correlation vs. Causation
The age-old confusion between correlation and causation is alive and well throughout our daily living. For example, everyone knows that higher speed limits cause more highway deaths, right? Actually, today's higher speed limits, combined with better vehicle design, have resulted in a traffic fatality rate that is less than half what we had under the national 55-mph limit! Which part is correlation, which causation?

The same kind of question, and confusion, may lead us to false conclusions about the success or failure of our attempts to make positive change in work-related outcomes.

Recently, we hosted a seminar on work-related risk reduction. The participants, all professionals in the area, were asked two questions: What has happened to on-the-job injury rates over the past three years? The answer, a group consensus: They have declined, by nearly 33%.

The second question: What has caused the decline? Again, with a high degree of agreement: The improvements in safety programs, including training, inspection, enforcement, and systems design.

I can't tell you this answer is wrong. I can agree there is a correlation between the increased emphasis on these things and the decline. But, what if it is not the cause?

Over the past three years, there has been a national decline in rates of turnover, and the graph shows how closely that parallels the decline in injury rate. What if all or most of the decline can be explained as an effect of lower turnover? It is widely believed that the turnover decline reflects the tougher job market in a down economy, and the rate is expected to rebound to historically higher levels when the economy itself rebounds, and the job market improves.

If this proves to be the true causal agent, we will discover that we rapidly return to the high occupational injury rates of the turn of the millennium, and we may be called to account for the billions of dollars spent in safety, training, inspection, etc.

Bureau of Labor Statistics figures for the Manufacturing sector show that, in 2002, a worker with less than three months on the job was more than twenty-seven times as likely to suffer a lost-time injury, when compared to a worker with over five years on the job.

Studies of programs designed to reduce turnover have often shown, as a side effect of success, reductions in occupational injury rates. In one manufacturing study reported in Vol 1 #2 of this publication, a 33% reduction in injuries accompanied a 30% reduction in six-month hiring failures-and both were accomplished with a 40:1 return on investment!

As your business concentrates on improving safety and reducing risk, consider adding a strategic hiring/turnover reduction program to the mix. Assessments, properly used, can help you meet your risk management goals.