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13 July 2018 | Comment | Article by Mark Harvey

Your fitness tracker could impact a personal injury claim


An international survey carried out in September 2016 by GfK – a market research institute – suggested that one in three people across the globe currently monitor or track their health and fitness via an online or mobile application or using a fitness band or a smart watch.

The number of people using this sort of technology to measure their general health and/or to record particular fitness activities is predicted to continue to rise. Can the data from such devices be useful in determining the circumstances in which an accident occurred as well as assessing the value of a potential claim?

Despite the prevalence of fitness trackers in modern day life, there does not appear to be many cases in England and Wales in which the data has been used. However, that’s not to say that it isn’t being used.

One of my colleagues has utilised data extracted from a client’s Strava application to establish information pertinent to liability issues in a case he was dealing with involving a collision between his client, a cyclist, and a motor vehicle.

Other colleagues have reported that in a case they are handling the data on their cyclist client’s Strava application has been used to identify the speed he was travelling at in the moments leading up to and at the time of the accident. In that case that information was very helpful in enabling the parties to reach a settlement two months before trial.

So why the lack of reported cases?

There is a suspicion that this type of evidence has been used but due to cases settling in advance of trial it hasn’t garnered much publicity or visibility. In England and Wales less than 4% of all issued civil claims proceed to a trial. Therefore the fact that none of the reported judgments refer to the use of data from fitness trackers cannot be relied upon to make a bold assertion that this sort of data just does not get utilised. Anecdotal evidence suggests that it is starting to be used to good effect particularly in relation to liability issues.

So what are some of the challenges that might be faced when using this data?

One of the main issues will be how reliable the data extracted from the tracker actually is.

There have been many reports about the limited reliability of fitness trackers. A study from Stanford in 2017[1] found that, in terms of measuring energy expenditure (e.g. the amount of calories you have burned), the seven wrist-based fitness trackers tested had median error rates of between 27% at best and 92.6% at worst. Heart rate measurements were significantly more accurate than the measurements of energy expenditure. The study team concluded that it is very hard to train an algorithm that would be accurate across a wide variety of people because energy expenditure is variable depending on someone’s fitness level, height, weight etc.

In addition, the settings against which the data is measured might not be correct or might otherwise be unreliable.

Whether the data a solicitor is seeking to rely upon is accurate enough to be admitted may depend upon what they are trying to establish.

For example, If they are trying to establish someone’s location, their speed over a distance or the route they travelled, which may be relevant on issues of liability, given that many fitness trackers that record this sort of information will be linked to GPS data it may be easier to establish the reliability of the data.

However, if they are trying to establish evidence relating to the health of an individual this will be more difficult given the variable reliability of trackers measuring energy expenditure. unless there is other evidence that corroborates the picture painted by the data obtained from the tracker

In Summary

Fitness trackers are a relatively new phenomenon and it is probably true to say that their development, while not in its infancy, will continue to progress for some time to come.

The very sparse reports of their use as evidence in personal injury litigation suggests that, while they have significant potential to be of importance to parties dealing with such claims, their impact to date has been limited. The biggest barrier to their use at the current time would seem to be concerns about their reliability, which is reported to be highly variable depending on issues relating to both the product and the user. If reliability can be improved then they could be obvious sources of evidence for personal injury cases in the future.

[1] https://newatlas.com/fitness-tracker-data-accuracy-study-stanford/49699/

Author bio

Mark Harvey is a Partner in the claimant division. He has obtained compensation for many individual victims of common but defective consumer products as well as victims of accidents overseas and arising out of travel generally.

Mark is the court appointed lead solicitor coordinating over 1,000 claimants in a group litigation order (GLO) arising out of the recall and health alert relating to the French manufacturer’s PIP silicone breast implants.

Disclaimer: The information on the Hugh James website is for general information only and reflects the position at the date of publication. It does not constitute legal advice and should not be treated as such. If you would like to ensure the commentary reflects current legislation, case law or best practice, please contact the blog author.

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