Real and virtual visual site assessments

A visual site assessment – either Real or Virtual – is a valuable task in the investigation of a personal injury or a failure in the built environment. I explain this in the Bundle of Blogs below that I posted in the past. This type of assessment is particularly valuable during COVID-19.

In a Real assessment, the forensic expert does the following tasks:

  1. Gets briefed by the client
  2. Reads documentation on what happened
  3. Goes to the scene of the personal injury or failure,
  4. Examines the exposed surfaces at the site
  5. Notes what’s there and what’s not
  6. Takes some measurements
  7. Also some photographs
  8. Perhaps gets video from a drone
  9. Gets “calibrated” to the site (Ref. 1)

S/he does not do the following that come later if required:

  1. Look below the surface
  2. Take things apart
  3. Do intrusive field testing, or
  4. Laboratory testing

What is done during the Real assessment process is not too much different from the SOAP (Subjective Objective Assessment Plan) and Differential Diagnosis processes in medicine. (Refs 2, 3)

A lot of data and evidence is gathered this way, sometimes enough to reason to a conclusion and form an opinion on cause sufficient to resolve a dispute or settle a claim.

A Virtual assessment – sans site visit – is also good, and sometimes enough. If it has a shortcoming, the expert doesn’t get “calibrated” to the site as well as he might. Nor get his hands dirty and mud on his boots. (Ref. 4)

I’ve done several virtual assessments including one a few months ago at the scene of a trip and fall accident. Others were of retaining wall failures, a bridge collapse, several building collapses and a trench cave-in.

One assessment resolved an 11 year dispute after a four month forensic investigation. A person was injured by ice falling off a structure. In hindsight, that visual site assessment was half real and half virtual – I examined the exposed surfaces with binoculars from across the street.

At the time of this investigation I got insight into the formation and risk of ice on structures during a ski trip to Mont Comi on the Gaspe Peninsula. The penny dropped as I came and went from the ski lodge. Ice formed at the eaves trough till it got too heavy and fell off. Signs warned skiers of this. I also saw ice on buildings during a visit to my daughter’s horse farm in Maine. Forensic engineers are working even when they’re not.


In the following, I’ve listed a few recent blogs on Real and Virtual visual site assessments that are particularly relevant in COVID-19 times. I’ve posted others in the last nine years but the following are enough.

At the end of the day, while a visual site assessment, real or virtual, is often enough to resolve a dispute or claim, there are situations where field work must be carried out.

A Bundle of Blogs: The value of Real and Virtual Visual Site Assessments

  1. How do you carry out a forensic investigation during a pandemic? Posted January 8, 2021 The blog notes the value of plain old engineering experience. But, when coupled with a virtual visual site assessment, invaluable and more reliable still. Three engineers found the same cause of a building collapsing, two based on experience alone. The third based on experience plus a virtual visual site assessment.
  2. COVID-19 and forensic engineering investigation. Posted May 7, 2020 It struck me one morning while walking my dogs that forensic engineering investigation is not prevented by COVID-19.  Experts often work alone as principal investigators conferring with other specialists as needed.  Many of the most experienced experts are sole practitioners.  We already “work from home” in a sense and have for years.
  3. COVID-19 and an initial forensic task a.k.a. a visual site assessment, sans social distancing. Posted June 1, 2020 The blog reminds us that the visual site assessment is carried out by a lonely expert whether on site or virtually. Social distancing is not an issue. It also reminds us that it’s an essential task that should be done before the dust settles at the site of a failure or accident.
  4. Get on site and do a forensic visual assessment before COVID-19 returns. Posted September 10, 2020 This seems a bit of a joke this day as a fourth wave threatens us. But the blog does contain nice comment on how document review, virtual site assessment and on-scene assessments work together to yield a lot of data and evidence on the cause of a failure or accident.
  5. Can you “calibrate” a forensic expert? Posted June 23, 2020. This is a good read, a bit of an eye opener as to what happens to an expert when s/he goes to a site and collects hard data. An expert does get “calibrated” to the scene of an failure or accident during a visual assessment. The process also happens to some extent during a virtual assessment.
  6. Counsel: Your case benefits when you visit the scene of a personal injury accident or engineering failure. Posted April 30, 2016 In a sense, this was a visual site assessment by counsel in a slip and fall case that paid dividends. He went to the accident site to watch me carry out skid resistance tests. Management later cancelled further expert work including submission of a report on the skid testing because the firm underestimated the cost of expert services. All that my client had to argue his case was his viewing of the field testing, photographs he had taken and my verbal comments on the results as we drove back to the city.
  7. “Technical” visual site assessments: Valuable, low cost, forensic engineering method. Posted September 4, 2012 The blog explains that the visual site assessment is a basic initial task in a forensic investigation. Sometimes it’s all that is necessary in the gathering and analyzing of data on the cause of an accident or failure.

Examples of Real and Virtual Visual Site Assessments

  1. My personal slip, trip and fall accident. Posted September 2, 2021
  2. Why did the four story building collapse during construction in London, Ontario? Posted December 31, 2020
  3. What can you get from a virtual site assessment about the cause of a leaning retaining wall? Posted November 13, 2020
  4. What can you get from a virtual visual examination of an accident scene. Posted August 28, 2020
  5. Wind, construction crane and inadequate cross-bracing caused Edmonton bridge failure: An initial hypothesis. Posted March 27, 2015
  6. Falling roof ice injures man. Posted January 18, 2013
  7. Gabion retaining wall collapse results in litigation. Posted February 9, 2013

Related to the blogs in the Bundles above

  1. The reliability of an educated guess on the cause of a failure or accident. Posted October 22, 2020.
  2. Where does an expert’s initial hypothesis come from? Posted February 25, 2019. Updated March 18, 2019


  1. Can you “calibrate” a forensic expert? Posted June 23, 2020
  2. Using SOAP notes in forensic engineering investigation. Posted February 6, 2014
  3. Differential diagnosis in medicine and forensic investigation, and soft, initial thoughts on cause. Posted December 20, 2019
  4. An expert’s “dirty hands and muddy boots”. Posted December 20, 2013

(Posted by Eric E. Jorden, M.Sc., P.Eng. Consulting Professional Engineer, Forensic Engineer, Geotechnology Ltd., Halifax, Nova Scotia, Canada September 14, 2021   

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