It doesn’t rain but it pours guidance on writing expert reports

I thought this on reading the guidance for presenting a claim in the Small Claims Court of Nova Scotia.  I was researching material to do with a case at the time.  You can read the simple guidance at

Experts could do worse than visit this site for more guidance on carrying out a forensic investigation, analysing the results, forming an opinion on cause and presenting their findings in an unbiased, objective expert report.  This is particularly the case when it comes to writing the expert’s report – which has been found wanting. (Ref. 1)

The guidance at this web site states that you need evidence to support a claimEvidence is anything that helps prove a fact important to your case.

Eureka! How is this any different than the evidence needed to help prove the facts supporting your opinion on the cause of a personal injury or a failure in the built environment?

Also quite important in the guide is the note that when you testify in court you’re telling your story.

Keep the forensic story, like the testimony in court, evidence-based, jargon-free and simple:

  1. Tell ‘em what you’re going to tell ‘em
  2. Tell ‘em – with a beginning, a middle, and an end
  3. Tell ‘em what you told ‘em

It’s nice how simple guidance on preparing a claim for Small Claims Court can help us carry out well substantiated forensic investigations and write evidence-based expert reports.  Realizing guidance is needed (Refs 1, 2 and 3) and that there’s detailed handbooks out there (like Ref. 4) should be enough.  The Court’s guide is more of a reminder – a gentle rain rather than a down pour.


  1. Is there an argument for a peer review of a peer review?  Posted January 11, 2020
  2. Ridding peer review of potential bias.  Posted December 30, 2019
  3. What good are civil procedure rules governing experts?  Posted January 30,2020
  4. Mangraviti, Jr., James J., Babitsky, Steven and Donovan, Nadine Nasser, How to Write an Expert Witness Report, 2nd ed, 2014, 560 pg, SEAK, Inc., Falmouth MA, USA

What good are civil procedure rules governing experts?

Particularly if most disputes don’t go to trial or a tribunal?  But, isn’t that the purpose of the rules, to keep disputes out of court?  Like Rule 55 in Nova Scotia?  That’s true, and they do this by setting a high standard for an expert report.  The parties, on reviewing the report, would often enough see their way clear to settle.

However, I wonder if a lower standard of report is now being accepted?  Why pay for a higher standard if the dispute is unlikely to go to trial or a tribunal?

The standard appears to be lower in the Maritimes if a survey I did of seven engineering experts in NS and NB is any indication.  I asked them, To what extent do you see bias and poor analysis and reasoning in rebuttal expert reports?”.  The consensus was almost always. (Ref. 1)  I’m certain, the question could be asked about expert reports, in general, and the reply would be similar.

(I wonder if the bias and poor reasoning we see in some expert reports in the Maritimes appears in some of the reports of the experts surveyed in Ruth Corbin’s pilot study of 152 experts in Canada?  The study noted the expert’s view of their role in the judicial process. (Ref. 2))

The civil procedure rules are a short, simple guide on carrying out a forensic investigation and writing an expert report, but what good are they if they’re not followed?

And why aren’t they?  Cost?  Possibly.  An understandably, poorly informed non-technical client?  Likely.

I don’t think the rules are going to be taken down any time soon.  I think what’s expected of the expert must go up.  This must come to some extent from a better informed client about the benefits – including cost-benefit in the long run for both client and injured party – of a thorough investigation and a well written, objective expert report.

What’s being submitted now for expert reports and rebuttal expert reports are easily reviewed by unbiased, experienced technical experts – easily “slammed!” to use an expression by one of my survey experts.

(I’ve got a problem with that word “slammed” as reflecting an attitude at odds with a simple desire to seek the truth when peer reviewing another’s expert’s report.  But, it does indicate what can happen to a poorly written report)

What are the benefits to the expert and the client of following the rules for likely out-of-court settlements?  I think the following quote is a good answer:

An expert’s report is a critical, make-or-break document.  On the one hand, a well-written report will make testifying later at discovery and trial much easier (if it goes that far, and pre-trial decision making more reliable) and will enhance the reputation of the expert.

On the other hand, a poorly written report will damage the expert’s reputation, can turn deposition into a nightmare, and can become a career-ending event (and an out-of-court settlement or dispute resolution into something less than fair for some of the parties)” (Ref. 3) (The parenthetic comments are mine)


A little aside.  What’s in Ref. 3 – How to Write an Expert Witness Report – for counsel and insurance claim’s managers if you were to buy it – which I think you should?  Maybe even give a copy to your expert?

This 2nd edition, massive, 560 page, 8″ x 11″ book is a step-by-step guide for experts written by lawyers.  It’s based on a review of 1,000s of expert reports, case histories and insurance settlements.  It will give you great insight into what you should be getting for your expert-report dollar.  It’s far more comprehensive than civil procedure rules governing experts, as good as they are.

(This is not a commercial for the book.  I use it and it’s excellent!)


  1. Is there an argument for a peer review of a peer review?  Posted January 11, 2020
  2. How experts are helping break the expert evidence logjam. Posted April 30, 2018
  3. Mangraviti, Jr., James J., Babitsky, Steven and Donovan, Nadine Nasser, How to Write an Expert Witness Report, 2014, (the Preface), 560 pg, 2nd edition, SEAK, Inc., Falmouth MA


Is there an argument for a peer review of a peer review?

I wondered after a recent blog if there is an argument for a peer review of a rebuttal expert’s report. (Ref. 1) There’s a strong argument, if the evidence is any indication – evidence characterized, at the very least, by biased phraseology in the rebut.

In my blog I identified when peer review of an expert’s report could be done – as distinct from a rebuttal expert’s report – during the judicial and dispute resolution processes, and the involvement of the expert at each stage of a process.

I listed the stages in decreasing order of preference according to the involvement of the expert in organizing a peer review of his report.  The less involved the expert the more preferred the stage.  A peer review organized by the court or dispute resolution tribunal is the most ideal.

I included a rebuttal expert’s report in the list because it can be thought of as a review by a peer of an expert’s report.  I put it at the end of the list as least preferred even though the expert doesn’t organize it.  I did this because of the bias I see in rebuttal reports.

Based on what I’ve seen, and learned from other experts, rebuttal expert’s reports need to be peer reviewed.  A well reasoned and written rebuttal expert’s report can serve as a peer review of an expert’s report but that’s not happening.  They are not being prepared as required according to civil procedure rules governing experts, like Rule 55 in Nova Scotia.

My opinion is based on a survey of seven people in Nova Scotia and New Brunswick who provide expert services.  I asked them, To what extent do you see bias and a lack of analysis and reasoning in rebuttal expert reports?”.

The consensus was almost always.  Sometimes it’s due to sneaky bias that creeps up, unbeknownst, on all truth-seekers.  Other times – too often – it’s due to poor analysing and reasoning followed by poor report writing.  At times it’s blatant case-making for the client.

Also, often enough, the client, not being a technical expert in the issue, is unaware of his expert’s rebuttal report’s vulnerability to peer review.


So, based on a survey of well experienced experts in the Maritimes, rebuttal expert reports are likely biased and poorly prepared and there is a strong argument for peer reviewing them.  And the guidance in civil procedure rules like Rule 55 in Nova Scotia make it easy to do and cost effective.  It costs money in longer trials, longer dispute resolution processes and questionable insurance settlements if a rebuttal expert’s report is found wanting – as most are now.


  1. Ridding peer review of potential bias.  Posted December 30, 2019

Ridding peer review of potential bias

Forensic investigation must be as thorough and objective as scientific research.  Peer review in science ensures that the research is well done.

Unfortunately, peer review in forensic work is not carried out very often.  And when it is there is a risk of bias in how it’s done.  This in spite of strict civil procedure rules governing experts and their reports.


Peer review in science is a process of evaluating scientific work, by an expert or a group of experts in the related field.  The scientific worker may or may not know the reviewer(s) – a blind peer review.  Similarly, the reviewer may or may not know the worker. (after Ref. 1 and Dr. Google)

Bias, or unreasoned judgement, can be blatant, or it can be unintended, sneaking up on us out of the ether. (Refs 2, 3 and 4)

Getting rid of bias in peer review is essential to forensic investigation.


The penny dropped for me on a better way compared to current practice when I got an e-mail from a reader, Ruth Corbin, after she read a blog I posted on peer review.  (Refs 5, 6)  A quick reply to Dr. Corbin included my initial thoughts on how I think we can get rid of bias.  These are bulleted below including some additional thoughts.

At present, experts investigate the cause of a problem.  They write a report on their investigation and findings.  The expert’s report goes to their client, the insurance claims adjuster or the civil litigation lawyer, and from there to the court or dispute resolution tribunal.  The investigation and report are seldom peer reviewed.  Except in a sense when they are rebutted by the expert for an opposing party.

Just how unbiased is the rebuttal report?  If phraseology in some reports is any indication, not much.

(You’ve all seen this phraseology, I’m sure.  Just to be really sure though, I’ll update this blog in future with some examples)

A peer review doesn’t have to be a crude denunciation or vetting of an expert’s work.  We can get rid of blatant bias.  We’re all here to serve the judicial and dispute resolution processes.  Finding errors and omissions and fixing them serves that purpose.

A peer or rebuttal review a little closer to that in science would help, one that involves the expert as little as possible in the organizing of a peer review of his work.  I think peer review procedures like the following will help, in decreasing order of preference:

  • The court or tribunal retains the peer reviewer independent of the expert or his client.  This in the spirit of peer review in the scientific community.
  • All the experts engage in “hot-tubbing” session, give their evidence concurrently and agree a joint report. (Refs 2, 7)
  • The lawyer or adjuster retains a peer expert to review his work.  Because s/he wants a thorough and objective explanation of issues unfamiliar to the court or tribunal.  But third in preference because the lawyer does have his interests.
  • The expert retains a peer reviewer.  Because she would like to think they have done thorough work and reasoned well, particularly in the more empirical applied sciences like some medical and engineering specialties.  But fourth in preference because perception is everything in some fields of study.  An expert hiring someone to check his work might not look good.
  • The rebuttal expert peer reviews the expert’s work.  I include this procedure because it’s a procedure that is sometimes followed.  It can work if the rebuttal expert pushes back against bias.
  • No peer review at all of any kind.  The procedure assumes the expert’s work is thorough and objective and unbiased.

I believe the risk of bias is low when the court or dispute resolution tribunal arranges the peer review and high when the rebuttal expert does this.


We can get rid of some or almost all bias in peer review of forensic investigation and expert services.  There are several methods for doing this.  What we chose will reflect our commitment to change and what we’re prepared to accept.  We’re accepting a lot of potential bias now.


  1. Merriam-Webster dictionary
  2. Biased experts cured with a soak in the “hot tub”.  A blog posted January 31, 2017 at
  3. Expert witness forum looks at bias and other touchy subjects in forensic work. Posted March 8, 2018
  4. Are experts being broadsided by bias unbeknownst to them?  Posted April 12, 2018
  5. A Bundle of Blogs: On the need for peer review in forensic engineering and expert services.  Posted November 29, 2019
  6. Corbin, M.Sc., Ph.D., LL.D., Ruth M., Chair, Corbin Partners Inc, and Mediator, Corbin Estates Law, Toronto
  7. “Hot-tubbing” experts reduce the cost of civil litigation and ensure objectively.  Posted March 31, 2018


Differential diagnosis in medicine and forensic investigation, and soft, initial thoughts on cause

The phrase “differential diagnosis” caught my eye recently in light of some tendency in forensic engineering for the injured party to take the expert’s initial thought on cause as gospel and run with it.

Yet the forensic expert’s initial thought – an initial hypothesis – is based on just a little evidence and likely, quite subjective evidence.  For example, a briefing by the client, a  read of some documents and perhaps a walk-over survey of the accident or failure site.

Sometimes that thought/hypothesis is subject to revision like happens in the scientific method – and an embarrassment to all concerned if counsel decides to take the case or the claims manager agrees a settlement.

(Scientific method: A method or procedure that has characterized natural science since the 17th century, consisting in systematic observation, measurement, and experiment, and the formulation, testing, and modification of hypotheses. Ref. 1)

Differential diagnosis is a medical process.  It occurred to me that forensic experts could learn from medical doctors.

Differential diagnosis is the development of a list of possible medical conditions that might explain a patient’s symptoms.  The list goes from the most likely and urgent at the top to the least at the bottom.  The process involves several phases like forensic investigation involves several stages.  The early phases/stages are subjective in nature.  The process is well developed in medicine as explained by a friend and also Dr. Google. (Refs 1 and 2)

The phases of a differential diagnosis and their similarity to a forensic investigation are a little like the following:

Phase #1 Take history

In medicine, take a history from the patient about what she’s experiencing.  Interrogate and ask questions like a detective.  Try to figure out what’s going on.

In forensic work, take a briefing from the injured party or their counsel or claims manager about their slip and fall accident or the damage to their building.  Ask lots of questions.  Read existing documentation.  Consider different categories of accidents or failures.

Phase #2 Physical examination

Look, feel and listen.  Take the patient’s pulse and measure his blood pressure.  Examine him orally.  Listen to his chest (with a stethoscope).  Do a percussive examination (tap body with fingers and note the sound)

Walk over the site and visually examine the accident or failure scene and the structures there.  Measure and determine the condition of the structure before and after the failure.  Photograph and measure features characterizing the scene.  Take aerial video of the scene from a drone.  Excavate test pits and note the subsurface conditions.  Carry out initial skid resistance tests of the floor at a slip and fall accident. 

Phase #3 Additional investigative tests

Carry out additional tests like blood work, X-rays, MRIs and stress tests.

Take samples and do laboratory tests of the physical properties of materials that failed.  Do field tests and sample and test the physical properties of the soil in the field and laboratory.  If necessary, do additional skid tests of the floor.

Phase #4 Data analysis and interpretation

Analyse data and test results and identify conditions that could account for the patient’s symptoms.  List from most likely to least likely – the differential diagnosis.  Look at the most probable diagnosis at the top of the list then go back to Phase #3 and order more tests to confirm depending on how confidant you are.

Study the data, look at how different pieces of data relate and support one another and relate to possible causes of the personal injury or the crane or building collapse.  Identify the probable cause(s) of the injury or collapse.  If necessary, return to the site to check and confirm earlier findings.

Phase #5 Treatment

In medicine, prescribe a treatment of the condition with medicines, life style changes, diet, etc.  Monitor the condition and if improves good.  If no improvement, consider the dosage of medicines and the extent of other changes.  If none or not much go back to the previous phase and reconsider the differential diagnosis.  Treatment is the prescription, the plan in SOAP. (Ref. 3)

In forensic work, report the most probable cause of the accident or failure.  Recommend how the damage can be fixed and the cause of the accident or failure eliminated.


I see the differential diagnosis process as an elaboration of the SOAP process that is also followed in medicine: (Ref. 3)

1. Gather Subjective data.  Take a history from the patient in medicine and a briefing on the problem in engineering.  Reflect on why the patient is hurting and the different categories of structural failure in engineering.

2. Get some Objective data.  Like blood work and X-rays in medicine and measurements and field and laboratory tests in forensic investigation.

3. Analyse the data.  Study, identify and list the different medical conditions indicated by the data that could account for the patient’s symptoms.  And in forensic work, the different causes that could account for the personal injury or the crane or bridge collapse.  The list is the differential diagnosis in medicine and the possible causes in a forensic investigation, going from the most likely cause at the top to the least likely at the bottom.

4. Prescribe treatment.  For example, identify life style changes, diet and/or medications to fix the medical condition and make the symptoms disappear.  In forensic work recommend how the damage can be repaired and the cause removed.


Can you imagine the embarrassment to the medical doctor and the pain for the patient if s/he prescribed treatment based on the results of Phase #1 of the differential diagnosis process and he was wrong and the patient dies?  Everybody gets in trouble.

Fortunately, that doesn’t happen often in medicine.  Unfortunately it happens at times in forensic work – the client runs with the expert’s initial thoughts on cause.  A few years ago, an expert noted the occasional pressure on an expert during a forensic investigation to find support for those initial thoughts.


So, the next time you’re getting a medical check-up think about the forensic expert and hope the doctor doesn’t go with his initial thoughts on the cause of your symptoms.  And if you’re the forensic expert, go out of your way to help your client, the injured party, understand that an initial thought on cause is not necessarily a final diagnosis.  It’s at the front end of the subjective-data-collection-stage and a soft thought.


  1. Dr. Google
  2. Personal conversation with Dr. J. Nasser, Halifax, a retired ear, nose and throat surgeon and a former dentist
  3. Using SOAP notes in forensic engineering investigation.  Posted February 6, 2014



A Bundle of Blogs: On the need for peer review in forensic engineering and expert services

Take your pick: Get your expert’s report reviewed by a peer, or rebutted by a peer.  A peer review has a scientific ring to it.  A rebuttal review has an aggressive ring.

If a peer review finds that you’re out on a limb with errors and omissions in your expert’s forensic investigation and report – it happens – you can back track and correct them.  If a rebuttal review finds this, you’re stuck on the limb and on the defense.  They both cost money but money spent on peer review is better spent and less embarrassing.

I’ve thought this for a while resulting in the following blogs over time.  Also that it was time to bundle them together.

I think blog #3 on controlling review costs is quite a good read.  It explains the different ways you can retain an expert and how each can be peer reviewed.

If you’ve got time to look at the blogs, you might start with #5 the first one I posted in 2013.

The Bundle

  1. Eureka! Peer review is good case management.  Posted November 16, 2018  A pithy, short blog on a Eureka! moment I had that emphasized the value of peer review at any stage of the civil litigation or insurance claim resolution process.
  2. Peer review pays off – 17 years later.  Posted May 5, 2017  A long time to wait and not your normal payback period – more like a few months.  This is case history that explains how a client was spared the lost of many 10s of 1,000s of dollars.
  3. Peer review costs can be controlled.  Posted January 22, 2016  The answer is in how you retain an expert.  You have a choice of eight different ways.  There’s a quote at the end of this blog that really makes you think.
  4. Peer reviewing an expert’s report ensures the justice system gets what it needs.  Posted January 15, 2016  I emphasize the need for peer review again and note that it is provided for now in the remediation of contaminated sites – environmental engineering.  I reviewed 16 references in drafting this blog.
  5. Peer review in forensic engineering and civil litigation.  Posted November 26, 2013  I explain the need for peer review in forensic work as perceived by a consulting professional engineer.  It was prompted after I read four poorly written “expert” reports.

Site analysis in forensic engineering investigation – from the simple to the complex, then back to the simple using drones

Terrain or site analysis using aerial video – looking at pictures taken from the air and getting information about a site – has come full circle, from simple to complex, and back to simple.  I’ll tell you how in the following, and why that’s good for forensic investigation.  Including – for certain in the future – a first-in-Atlantic-Canada aerial video.

It’s simple terrain analysis when the aerial video or photograph is taken near the ground – a few 10s of feet high.  The resolution and detail are good and anyone can look at the video and get evidence and data from it.  No special skills and software are needed.  Forensic experts like that: Reliable, precise evidence easily got and understood by everyone, including the client.

It’s complex when aerial photographs are taken from high in the sky – 1000s of feet.  The resolution and detail are not so so good and special skills are needed.  For example, skill in photogrammetry in the past as well as today, and also knowing how to use different software.

(Photogrammetry is the science of making reliable measurements between objects with the use of photographs and especially aerial photographs (as in land surveying and mapping).

(Terrain is a geographic area or piece of land.  It can also mean the physical features of a tract of land.  Also, a stretch of land, especially with regard to its physical features)


The simple terrain analysis today might be more correctly thought of as site analysis.  Site analysis is the type of analysis done on small, compact sites where most personal injury accidents, structural failures and problems occur rather than on large tracts of land – for example, the site of the accident, or the building or crane collapse.


Traditionally in terrain analysis, you look at the ground surface of quite large tracts of land as captured in aerial photographs.  You identify the physical features characterizing the surface, assess how the features relate to one another, then assess how the individual features and their relationships are relevant to your interest in the terrain.

For example, you might want to construct a road in an unmapped area.  The location and nature of features like hills, valleys, steep slopes, streams, forest, flora, existing structures and the underlying foundation soils are all relevant to what you want to do in the area.

Why not just go for a walk in the area and see for yourself?  That is done to some extent and is called ground proofing - confirming that the features you’ve identified in the aerial photographs are what they seem to be.  But for large, unmapped areas it’s not practical, maybe not safe either.

I worked for an Australian firm that selected preliminary routes for roads in Indonesian jungle by terrain analysis.  I’ve worked in jungle.  I learned after leaving one site that a man was taken by a crocodile in a mangrove swamp and eaten.


In the simple beginning of terrain analysis – the late 1800s – aerial cameras were taken aloft on balloons and kites and photographed the ground from quite low down.  As cameras improved this gave good detail from a different angle – above the site rather than at ground level.  In a sense, you saw your site in 3D – from the front, the side and above.  As good as it was, the area covered was limited.

Time passed and during WW 1 then more so in WW 2, cameras were taken aloft in reconnaissance planes, and understandably flew quite high and out of range of enemy guns.  Extensive areas were photographed this way and features of interest identified in the aerial photographs by the user.  Terrain analysis started to get complex.

More time passed and large areas of land were photographed this way and topographic maps made of the areas using photogrammetry.  All of Canada has been mapped from planes flying 1000s of feet in the air.

I’ve used these aerial photographs for years in my engineering work.  The planes flew at about 6,000 feet.  The detail was okay but not great, but better than not having a 3D aerial view of a site.

Various remote sensing methods were developed and increased the accuracy.  Photogrammetry continued to develop and LiDar also came along.

(Lidar (light detection and ranging) is a remote-sensing technique that uses laser light to densely measure the surface of the earth, producing highly accurate x, y, z measurements of a point on the ground.  In a sense, the location of the front, side and top of many closely spaced points on the earth – like the points defining the edge of a bog.  Lidar is emerging as a cost-effective alternative to traditional surveying techniques such as photogrammetry)

I used Lidar to investigate the cause of the foundation failure of a house and swimming pool in Cape Breton.  A Lidar map accurately showed the location of the edge of a bog and the probable location of compressible fill soil placed on a small area of the bog near the edge.  The foundations were constructed on the weak, compressible fill and bog and over time settled and subsided a lot – I remember 6.0 inches at one location.  It was an easy analysis and conclusion as to cause.

Still more time passed and in recent years simple drones fitted with video cameras came along – like motorized kites and balloons from the late 1800s -, and the cameras were much better too.  We got back to simple terrain/site analysis and the potential for taking forensic engineering investigation to another level is good.

Most recently for me, staging how an engineering failure might occur and photographing the scene from a drone fitted with a video camera.  I’m also looking forward to flying low and capturing the reenactment of a slip, trip and fall accident on video.  I’m certain it’ll be a first-in-Atlantic-Canada.

In hindsight, I wish now I had flown and got aerial video of the reenactment of a power tool accident that I investigated.  I got good video from the ground and the case was resolved, but aerial video of the reenactment would’ve been nice.  Next time.


I hope you’ve got an idea of site analysis and agree that simple is good.  Forensic experts certainly like it: Reliable, precise evidence, simply and easily got, easily analysed, understood by everyone, and explained jargon-free.  Not very high tech – simple low flying drones fitted with video cameras – but good and reliable.  You’ve got to agree.

It’s good like getting your hands dirty and mud on your boots tramping around on site on any occasion, including during ground proofing of the analysis of aerial video taken from low flying drones. (Ref. 1)

Also good like if you can measure it you can manage it. (Refs 2 and 3)  The measurements you can get from a screen-grab off aerial video are almost as good as those from a boots-on-the-ground land survey of a site.  The land surveyor in me knows this.

Simple is good, and it’s good to have come full circle and to be back where we started, in a sense, in the late 1800s.


  1. An expert’s “dirty hands and muddy boots”.  Posted December 20, 2013
  2. “If you can measure it you can manage it” – and do thorough forensic  engineering, and cost effective civil litigation.  Posted June 18, 2015
  3. If you can measure it you can manage it, even if it’s a real mess like a car or truck accident.  Posted June 23, 2016

A Bundle of Blogs: Aerial video of insurance and forensic sites taken with cameras mounted on drones

Aerial video of a site taken from a low flying drone is one of the best insurance and forensic investigative methods that I’ve used in a long time.  I’ve had excellent results since learning of this method in 2014 and my enthusiasm continues to grow – the following 15 blogs attest to that.

I attempted in the blogs to explain and demonstrate the worth of this method.  After 15 blogs it seemed time to bundle them together.  Particularly after the watershed development explained in Blog #1 below that enables me to plan a virtual flight over a failure or accident site days in advance and miles away.  New software and Google Earth make it happen.  But it can be very simple and low tech with a kid’s drone as explained in Blog #5.

What we’re doing is simple enough – taking aerial video of a site and analyzing it for data and evidence.  What’s different today is that we’re getting video from way down low, 10s to 100s of feet above a site.  In the past it was only possible from up high, many 1,000s of feet, from high flying planes.  Close to the ground, the detail captured with high resolution cameras mounted on drones is something else.

The following blogs describe what’s going on.  Several are of sites involved in insurance and forensic engineering investigations – see Blog #12 of an environmental investigation in the U.S.  Other blogs in the Bundle indicate the potential of up close aerial video.

  1. It’s here, cost effective, efficient aerial video for forensic investigation!  Posted October 8, 2019
  2. The drone will get the alleged killers, if they’re there.  Posted July 31, 2019
  3. What’s wrong with this (sinkhole) picture near Vancouver?  Posted February 20, 2019
  4. Reliable forensic evidence from drone photography: Aerial photography from way down low.  Posted October 31, 2018
  5. A kid’s toy drone can photograph the site of an engineering failure, a personal injury or a traffic accident.  Posted September 12, 2018
  6. Getting evidence in slip and fall accidents and building failures with video taken from a drone.  Posted August 9, 2018
  7. Drone video as a forensic technique is joined by drone photography as an art form.  Posted August 2, 2017
  8. “Unexpected” evidence and the importance of drone photography in forensic investigation.  Posted July 19, 2017
  9. Conference call on a “drone flight” reduces cost of civil litigation.  May 18, 2017
  10. Getting evidence with a low cost, low tech drone flight over a forensic site.  Posted March 31, 2017
  11. “Crewing” on a forensic drone flight.  Posted October 4, 2016
  12. U.S. civil litigation lawyer on using air photos in environmental litigation.  Posted November 18, 2015
  13. Fixed wing drones – another tool in forensic engineering investigation.  Posted November 4, 2015
  14. New forensic aerial photographic method proving extremely valuable.  Posted January 30, 2015
  15. A picture’s worth a 1000 words possibly many 1000s in forensic engineering with a new aerial photographic technique.  Posted January 15, 2014


It’s here, cost effective, efficient aerial video for forensic investigations!

It sounds like a commercial, but I was excited when I learned that you can now plan a drone flight and aerial video of a site from your office armchair.  Then see the virtual flight in 3D on Google earth – all before you drive to the site and days before the real flight.

You can get a preview of video taken during a virtual flight then, with a click of the mouse, change the drone’s flight path, speed and altitude, and the video camera angle.  Do this as often as you like, after as many virtual flights as you like, till you’re happy you’ve captured what you need – all from your armchair.

Needless to say, you can also plan as many different flights as you like over and around your accident, building or crane collapse site.

Then – after the client reviews all virtual flights on a CD and likes what he sees – drive to the site and fly it for real.  New software and Google earth make it happen.

Robert Guertin, Dartmouth, drone pilot and photographer gave me a demonstration a few days ago and it was impressive. (Ref. 1)


I retain Robert now to take aerial video from a drone of all sites where I’m carrying out a forensic investigation.  In the past we drove to the site with a drone fitted with a video camera and flew the site, seeing it for the first time from the air.  We made several flights – on site, not from an armchair – till we got the scene and the surrounding terrain on video in the detail I needed.

I got good data – I’m in awe about the worth of this forensic technique; including this one, I’ve posted 15 blogs on low level aerial video since 2015.  But sometimes I would get back to the office and after studying the video and doing some terrain analysis find that I might have flown additional paths or one or two in a different way and got even better data.

(Terrain analysis is another valuable technique in engineering – particularly now with low level aerial video – which I’ll tell you about later.  The terrain and the flora hold secrets to what underlies the site and what’s happened there in the past)


But, now we plan my flights from an office armchair. The software engages Google earth and brings up a 2D picture of the site on Robert’s desktop.  We’ve all seen these Google earth pictures.  I plan a flight over our site marking the path with way points on the 2D picture – a click of the mouse for each point.

The software then allows me to specify the height of the drone, it’s direction (heading in aviation) and it’s speed at each way point.  I also specify the camera angle, the view I want of my client’s site.

We engage Google earth again and ask the software to export the flight path’s file to Google earth.  This gives a 3D Google earth image of our site with the flight path superimposed.  We then fly this virtual flight path from our armchairs.

I have a look at what we’re getting during the flight.  If I don’t like what I see we disengage from Google earth, tweak the flight specification at each way point and fly again.  When we get a virtual flight and video coverage that collects the data I need, Robert produces a video clip and I send it to the client for approval.

On the client’s approval we drive to the site, load the flight plan to the drone and video camera and fly the site.  The software sends the drone on all the virtual flight paths we specified and the camera on board takes real video.  The video is put on a disk and the field work is done.

You can imagine the cost effectiveness of this forensic technique.  You capture what you need at your site then study and analyse the data later in your office.  It’s easy, productive and fun.  Forensic engineering investigation doesn’t get much better than this.


Virtual Flight Demonstrations

Robert demonstrated this technique for me at three sites, sitting in an armchair in his office.

A wharf in Nova Scotia.  This was one of Robert’s for-real commissions.  The client wanted the wharf repaired.  Robert was asked to fly the site and video the wharf and it’s present condition.  He planned distant, middle distant and close-up video of the wharf with the drone flying specified virtual paths, some at tree top level and others at scary, wave top heights.

The client was then sent a CD of the virtual flights for approval.  This was got then Robert went to the site and flew it for real, same as he’s done for me several times.  I saw all of both the virtual and real flights over and around the wharf – there was little difference between the two – and they were good.

The Dartmouth waterfront.  Robert then planned a virtual flight in 3D along the Dartmouth waterfront in front of Admiralty house then flew it as I watched from my armchair.  He specified all the flight and camera parameters identified above same as he would do if someone wanted to design and construct a building on the waterfront.

My home and neighbourhood in Dartmouth.  Finally, if I wasn’t impressed enough already, just to be sure, he then designed a virtual flight and video of my home and neighbourhood and flew it, as I watched from my armchair in his office.


  1. Meeting with Robert Guertin, Videographer, photographer, drone pilot, Millenium Film and Video Productions Ltd., Dartmouth, Nova Scotia


Am I a civil engineering expert?

I was asked recently, “Are you a civil engineering expert?”

I thought, civil engineering is such a broad field of study how can anyone be an expert?  But then I realized I have knowledge in the field enabling me to form an opinion that will assist the fact finder.  I have degrees and experience in civil engineering and the fact finder doesn’t.  My knowledge is greater in some areas of civil engineering and less in others, but still greater than the fact finder’s.

I was also quick to realize that I had considerable knowledge relevant to the issue being discussed at the time prompting the question of me.  Gaining that knowledge over the years provided insight into some of the sub-disciplines of civil engineering that many civil engineers might not get.

(Civil engineering is a discipline that applies physical and scientific principles to the design, construction, and maintenance of the built and natural environments.  Everything you see around you in the course of a day.  Its history goes back 1,000s of years)

Civil engineering sub-disciplines

You might still wonder if I’m a civil engineering expert when you see a list of some of the sub-disciplines of civil engineering:

  • Structural engineering
  • Foundation engineering
  • Geotechnical engineering
  • Environmental engineering
  • Coastal engineering
  • Water resources engineering
  • Forensic engineering
  • Geomatics engineering
  • Construction engineering
  • Earthquake engineering
  • Industrial engineering
  • Hydraulic engineering
  • Municipal or urban engineering
  • Transportation engineering

So many, and there’s still others.  But, look how a civil engineer can learn about different sub-disciples and be quite useful to a trier of fact:

How we learn about the sub-disciplines

I studied land surveying for two years before studying civil engineering and was licensed as a provincial land surveyor on P.E.I..  My summer work and for a year after I graduated from engineering was construction surveying for municipal water supply and sewage collection pipeline construction.  I also assisted construction surveying for 1.5 years during construction of an oil refinery.

So, some good insight gained into refinery construction, municipal work and geomatics engineering, formerly known as survey engineering.

I did highway engineering design work for a year in Vancouver.  I also got introduced to geotechnical engineering in Vancouver that included field testing of the sub-grade soils along 200 miles of highway in the Yukon.  I did foundation design and structural engineering while in Adelaide, Australia, and geotechnical engineering investigation of embankment failures in Brisbane and northern Australia.

All relatively short periods of time but real good introductions to the sub-disciplines.

I’ve not done hydraulic engineering or industrial engineering but that’s okay; you can’t do them all even if you do a lot.  (I did investigate the ground conditions for construction of hydraulic structures like dams and canals)

I eventually specialized in geotechnical engineering and did graduate work in the U.K. where I practiced for three years then continued in Canada.

Geotechnical engineers investigate and identify the different layers of soil beneath a planned construction site and test and measure the physical properties of these materials.  The soil properties are then used by engineers to design foundations that will safely support the structure planned for the site.

Geo engineers also design and monitor construction of earthwork structures like embankments, filled ground and highway cut slopes.

They must talk with owners, architects, site engineers, environmental engineers, structural engineers, foundation engineers, construction engineers – all sub-disciplines of one kind or another – to learn about the structure that must be supported on the ground.

Structures like low- and high-rise buildings, roads, bridges, dams, canals, retaining walls, towers, wharves, harbours and breakwaters, earthwork embankments and highway slopes.

Civil engineers get informed

You can just imagine as the years go by, how a civil engineer becomes quite well informed about these engineering sub-disciplines, and the different structures forming the built environment we live in.

(Hope your eyes are not glazing over yet – it really is like this in civil engineering)

Geo engineers overlap with environmental engineers

If you work in geotechnical engineering it’s not too long before you’re overlapping with environmental engineering.  Environmental engineers have a big interest in everything to do with water in the environment.

Surface water and ground water (the water table) changes the physical properties of soil and rock.  Sink holes like those in Oxford, Nova Scotia are a prime example.  Gypsum bedrock will support foundations quite nicely when dry but dissolves when exposed to ground water.

If you work in geotechnical engineering it’s also not too long before you’re doing Phase I, II and III ESAs – Environmental Site Assessments.  As a civil engineer, I’ve done a few of these over the years.  There’s a lot of overlap between the geotechnical and environmental sub-disciplines.

Sub-disciplines connect with their co-sub-disciplines

It’s the same with the other sub-disciplines and how they connect with their co-sub-disciplines:

  • Foundation engineers learn something about geo work, structural engineering and environmental engineering:
  • Highway engineers learn about geomatic engineering, and quite a lot about geotechnical engineering because highways sit on the ground;
  • Municipal engineers learn about geo engineering too because pipelines are buried in the ground;
  • Many sub-disciplines learn a little something about environmental engineering because engineering the built environment alters the natural environment
  • Structural engineers soon learn about earthquake engineering
  • Coastal engineers learn about the requirements of foundation engineers and environmental engineers

It goes on and on, the inter-relationship of the civil engineering sub-disciplines.

The principal engineer

However, it’s important for a civil engineer to know when to assume the position of principal engineer. (Ref. 1)

Principal engineers coordinate the work of other engineers and specialists to a common goal – in forensic engineering, to determining the cause of a collapse or accident in the built environment.  A principal engineer might be directing the efforts of construction engineers, structural engineers, mechanical engineers and crane operators in removing the collapsed crane from the multistory building in Halifax. (Ref. 2)

I’m not qualified to do structural and construction engineering but can develop some of the parameters enabling them to do their work, particularly soil and rock properties for foundation design.  I am qualified in earthworks design and also done a lot of materials testing and site inspection (earthworks and concrete construction).

I’m certainly qualified in knowing when to step back into the position of principal engineer, and well out of the way of those who know better.  I know when to retain one or more of the sub-disciplines because I’ve worked with them.

For example

I investigated a nail gun accident a few years ago.  It was easy for me to check if the nail gun appeared to work properly because I used one when I built my house from the ground up.

But, were hidden parts of the nail gun worn?  I’m not a mechanical engineer so I retained a specialist in nail gun repair to take it apart and tell me.

Was it poorly designed or manufactured?  I was ready to retain specialists in these fields.

First however, I decided to have the victim re-enact the nail gun accident while I took a video.  I take a lot of pictures and video in my expert work and this was easy for me to do as principal engineer.  The video of the re-enactment was insightful to say the least.

In other cases, I retained a structural engineer to guide me in underpinning a structure.  I retained a specialist in concrete design to guide me in retaining wall design.  I’ve got a call to a structural engineer now about bracing a deck structure so it won’t fall over.

Family doctors as principal investigators

The concept of principal investigator is not unique to civil engineering.  The medical profession adopts this approach all the time.

Your family physician takes a patient history, does a physical examination, may order some tests and may refer you to a specialist if s/he sees a potential problem.  He would coordinate the investigations of the other doctors and specialists into the problem.  The specialists would carry out thorough investigations and explain their findings in detail.  (Ref. 3)

It’s similar in construction when a general contractors hires carpenters, electricians, plumbers and roofers to do a job.  The general is the principal, the trades are the specialists.


So, what did I say?

Thinking through all of the above got me comfortably to the stage of answering the question put to me, “Are you a civil engineering expert?”.  What do you think I said?


  1. Lewis, Gary L., Editor, Guidelines for Forensic Engineering Practice, American Society of Civil Engineers (ASCE) Reston, Virginia 2003
  2. Why do I think the crane collapsed in Halifax?, posted September 20, 2019
  3. Personal communique with Dr. J. Nasser, Halifax, NS. September, 2019