Accident Details


What3Words
Domain: Policing, Medical
Year: 2021
Data Categories: Dynamic
Properties Lost: Integrity, Consistency, Aliasing

Summary:

What3Words use of homophones and plurals is alleged to have created difficulties in providing emergency services to persons in distress.

Details:

The What3Words application is intended to provide a means to easily and unambiguously define a location anywhere on the surface of the Earth. The ease with which the application can be used has led to its use by emergency services worldwide, for locating people in need of assistance — in safety terms, it has provided a useful form of mitigation, enabling emergency services to easily locate people, whether simply at the roadside, or somewhere on a mountainside. However there have been a number of claims that What3Words is not suitable for this purpose.

Accoring to the Telegraph (1 June 2021), Mountain Rescue England and Wales (MREW) claimed it had been told to go to 45 locations in the past 12 months which had turned out to be incorrect, whilst a rescue request that indicated a location in Australia actually emanated from a location in China. The article suggested that the problem was a combination of local accents and spelling errors. However the BBC reported that research by Andew Tierney indicates that the problem is more systemic, and reported:

  • The dictionary used by What3Words includes a number of homophones — words that have the same pronunciation, but different spelling.
  • Similar sounding words
  • Plurals

Cybergibbons illustrated the problem by presenting a list of thirty two pairs of words in the What3Words dictionary that appear to be extremely similar in pronunciation. They also pointed out a further algorithmic deficiency — that plural words can be followed by a word beginning with the letter “s”. Their examples include likely.stage.sock and likely.stages.sock, which denote locations on opposite sides of the River Clyde, and illustrate how in mountain rescue situations, even a small error in location could result in a serious delay to emergency provision.

Thus it appears that the system is working as designed, by providing a simple means to carry out geolocation. However a tool that was designed as a social application to help friends meet up has now been applied to a safety-related domain, without being re-engineered for that more demanding purpose. Three words will appear on the screen of the person requiring help, and if those same three words are used by the emergency services, the parties will be able to meet up. However that transfer is carried out by voice, where ambiguity can introduce error. The dictionary appears to contain homophones, plurals are used, and the algorithm permits the selection of pairs of words where the ending of one word cannot easily be distinguished from the start of the following word — each of these failings can lead to errors in communication.

Data properties involved: The ambiguities can lead to loss of Integrity, whilst the resulting distortion of world view is a loss of Consistency, and the Data Issue is one of Aliasing.

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