If your organization has an employee wellness program, you likely pay to have biometric screenings performed on your employees by a third party.  Why?  There really is just one answer to this question – it’s because you are concerned that if you allow your employees to self-report their measurements, the answers will be wrong, any analysis on that data would be suspect, and engaging the correct people in wellness will be more difficult.

So why then do several companies, and even biometric screening vendors allow a portion of biometric measures to be self-reported?  After all, the biometric screening vendors are in business precisely because self-reported data can’t be trusted, right?

There are 2 typical scenarios of partial self-reporting and they look like this:

1. The health screenings performed at the worksite include actual measurement of blood pressure, cholesterol values and blood sugar (e.g. fasting glucose), but height, weight & waist are self-reported by the employee.

2. Employees are referred to a local Quest Diagnostics or LabCorp franchise facility where again, blood pressure, cholesterol values & blood sugar are measured, but height, weight & waist are self-reported because it’s cheaper or more convenient than gathering all measurements objectively.

Given that height, weight & waist are the measurements where self-reporting is most common, it appears that companies believe these biometric values are:

A) more likely to be correctly known by the employee themselves,

B) less likely to be misreported by the employee,

C) or height, weight & waist matter less than other biometric values. So it’s okay if these values are collected less accurately.

Let’s investigate these positions individually.

Position A: Height, Weight & Waist are more likely to be accurately known by the employee at the time of the screening. FALSE

In the Journal of the Royal Society of Medicine, Scriban, Shelton, Chapel et. al. published the “Comparison of bias resulting from two methods of self-reporting height and weight: a validation study.” Interestingly, this study put the same people in two different positions. The first was to self-report height and weight with no expected follow up measurement in the near future. The second, at a later time, was to self-report height and weight when a follow up measurement was expected in the near future. The study did not find a significant difference in mis-reporting height & weight – the values were mis-reported by about the same amount and with the same frequency in both scenarios. The article goes on to say that “This, therefore, implies that ignorance is the principal driver in the loss of validity in these (self-reported) data.”

Position B: Height, weight & waist are less likely to be mis-reported. FALSE

In 2015, Preston, Fishman & Stokes published Effects of categorization and self-report bias on estimates of the association between obesity and mortality in the Annals of Epidemiology, that found “19.5% of a population that self-reported height & weight were misclassified in the BMI spectrum compared to when their values were directly measured. Among those that were obese, 32% were reported in the wrong category. And, in every reporting category for both sexes, the mean measured BMI was higher than the self-reported BMI, consistent with the general tendency to underreport BMI.”

Outside of ignorance, why would people mis-report these values when the data is confidential?

“Self-report bias is particularly likely in organizational behavior research because employees often believe there is at least a remote possibility that their employer could gain access to their responses,” according to an article titled Understanding Self-Report Bias In Organizational Behavior Research published in the Journal of Business and Psychology by Donaldson & Grand-Vallone.

Position C: Height, weight & waist are less important and inaccuracies can be afforded. FALSE!

As one may deduce from prevalence of research producing articles such as those above in abundance, the scientific community places a great deal of importance on accurate height & weight measurements because body mass index and values such as these are used to identify persons at risk for disease – a central tenant in the preventative approach that is employee wellness.

We, at Onsite Health Diagnostics, actually believe that height, weight & waist measurements may be the mostly correlated to employee wellness because a positive change in weight, BMI & waist is the most indicative of true lifestyle change. Whereas other conditions such as high blood pressure, high cholesterol and high blood sugar are easily medicated, there is no pill for weight loss. Significant weight loss requires either the commitment to surgery or the commitment to long-term, positive changes in diet & exercise or all of the above. Is this not what we are all really after in employee wellness?

Simple Answers and Solutions in Doing Screenings Correctly:

Studies show that people do not truly know their body weight or their height with accuracy. Their pants size is not their waist circumference either. Having a portion of the data self-reported, undermines the concept of having objective, direct measurements performed at all.

It’s like what Mr. Miyagi said about walking in the middle of the road. “Walk left side, safe. Walk right side, safe. Walk middle, sooner or later… get SQUISH just like grape.”

Don’t devalue your wellness program by allowing height, weight & waist data to be self-reported while you measure other values.