This post is a summary of a webinar on how to test biometric wearable devices. If you prefer, you can view the webinar here:

In today’s marketplace, there are more biometric wearable devices than ever before. But while there are plenty of options to choose from, it’s important to understand that not all biometric wearables are created equally.

Whether it’s for medical purposes or for lifestyle activities, accuracy in biometric wearables is of the utmost importance. Unfortunately, not all devices undergo the kind of rigorous testing needed to ensure accurate feedback for each of its users.

Read More: We’re just scratching the surface with biometric wearables for fitness and health

Since every individual is different and will use biometric wearables in a variety of environments, the only way to create a truly accurate device is through extensive laboratory and real-life testing that mimics these very same challenges.

Factors to Consider When Testing Biometric Wearables

When it comes to biometric wearables currently on the market, it’s important to understand the thoroughness of the testing of the device. Small sample sizes of testers and testing protocols not matching use cases are two common mistakes that can make a huge difference in how accurate a device is.

When testing a biometric wearable in a laboratory, there are a number of factors that should be considered when it comes to the user. Fitness level, the size and shape of the individual, differences in skin tone, and sweat rates are all variables that can affect accuracy in users of each device.

Here are a few of the other challenges a good laboratory test should investigate to ensure accuracy:

  • Skin tone: Every skin tone absorbs optical light in different ways. This is why a variety of different users with different skin types must be tested.
  • Optical noise: Noise from wind, workout equipment, and traffic can all affect the reading from sensors.
  • Blood perfusion: Poor circulation of the individual will make it difficult for the optical sensors to receive data. If a wearable is being tested for the wrist, blood circulation to the hands should be examined.
  • Sensor location: Where the sensor is placed on the body can affect data. In most instances, the ear is easier to measure than the wrist.

If you are looking for more detail on these factors and more, we wrote another post on how optical heart rate monitors work.

In addition to the challenges of each individual user, testing protocols that match use cases are a must when testing biometric wearables in the laboratory. For instance, if you’re creating a wearable for lifestyle purposes, testing needs to mimic the environment and duration of real-world use. While this might seem like common sense, not all companies test devices based on their intended use. If a product is being tested that will be used primarily by cyclists, most of the protocols should focus on creating use cases centered around testing on the bike.

At Valencell, we go to great lengths to make sure each device is tested across a multitude of different activities to ensure accuracy. This includes replicating the environment devices will be used in, various exercise intensities, and length of use. Without taking these factors into consideration, the accuracy of any one particular device cannot be guaranteed.

Read this: How Accuracy Happens In Biometric Wearables and Why It Matters 

What a Good Biometric Test Should Look Like

While other biometric wearable companies might claim to conduct extensive testing of their products, most do not have the staff, facilities, or volume of participants to back up their assertions. Valencell’s sports performance in Raleigh, North Carolina which includes a large portion of Valencell’s offices, along with an outdoor track, swimming pool and over 100 miles of greenways used to test outdoor activities was created to closely replicate the environment each of our customers’ products will face in the real world.

Test facilities should include equipment that enables meticulous testing of cycling, swimming, running, lifestyle activities, and a multitude of other workout scenarios to ensure accuracy no matter what the intended use. Since there can be large spikes and drop offs in input when interval training, strength training workouts, and circuit training workouts, these activities should also a big part of testing. Heart rate data at rest and testing in a variety of different weather conditions and sunlight intensities should also be taken into account—which are commonly overlooked. Without this ability to test each of these different workout scenarios in the laboratory, proper assessments of wearable products is extremely difficult.

Once the facilities are in place, the second part of any good laboratory test is to gain access to a wide range of participants. At Valencell, we’ve been lucky enough to be able to pull from a large pool of individuals of all ability levels. Each week prototypes are tested by participants from our pool of around 100 volunteers. But while volume is one thing, variety is even more critical. And because individual variances need to be considered, each new product should be tested on at least twenty different people—all of whom have contrasting sizes, shapes, and skin tones to guarantee all of our products will be accurate no matter the user.

Perhaps the most important part of any sound laboratory test though is having an experienced and well-trained staff on hand to evaluate the data. At Valencell, our team of scientists all come from a research and laboratory background and possess extensive knowledge of the core technology, how it is implemented and the nuances of testing biometrics on humans. This allows for a detailed analysis of the accuracy of the optical sensors during all each the workout activity conducted during the testing so fine-tune adjustments can be made when needed.

Read More: Biometric sensor accuracy claims that are too good to be true

An experienced scientific staff also has the ability to scrutinize even the most minute of details that can affect results, such as how a clasp on a heart rate strap has been attached or the hole placement on a wrist wearable. This kind of attention to detail, when combined with the right facilities and variety of test subjects, is what is needed for a sound biometric wearables test in order to produce accurate devices. For more information on testing devices, check out our post on heart rate reviews and why you can’t test just one device. 

For more detail on Valencell’s extensive laboratory testing procedures of each of its biometric wearable products, watch the webinar above from Dr. Chris Eschbach, who is the Director of Valencell’s biometrics laboratory. You can also reach out to us at info@valencell.com for more detail.