Day 128: Methods and methodology

In the competitive theatre of the Montreal tobacco trial, there are occasionally dramatic shifts between scenes. Today was one of those days. Yesterday's squabbling about old grievances gave way to today's high-toned and civil exchange about epidemiological methods.

The curtain on today's episode did not came up until the afternoon, as the morning's hearing had been sacrificed to an unspecified scheduling conflict. When it did open, the courtroom setting had been tweaked for the re-appearance of Montreal's noted epidemiologist, Jack Siemiatycki.

The counsel for Canada's smallest multinational tobacco company, JTI-Macdonald, had moved to the defence's front seat, which is on Justice Riodran's left hand side and beside the witness. Sitting beside Guy Pratte at the front desk was Kevin LaRoche, who seems responsible for preparing for scientific witnesses for JTI.

With Mssrs Pratte and LaRoche in charge of the day, I expected a smooth ride. These players don't go in for the theatrics, pissing matches and games of silly bugger that some of their colleagues excel at. But even against my relatively high expectations for the day, I was pleasantly surprised.

It was these two men who would lead the remaining cross-examination of Mr. Siemiatycki, a witness whose report is very damaging for the companies. The report (Exhibit 1426.1) concludes that in recent years the number of Quebecers made sick as a result of smoking these companies' brands is four times the population of Outremont:

"From 1995 to 2006, there were 110,282 Quebec residents who suffered from one of the four diseases and who would have had probability of causation greater than 50% that the cause was cigarette smoking."

Epidemiology 401

In trying to challenge the methodology used by Mr. Siemiatycki, this duo had gone to obvious efforts to bone-up on the content, to refine the issues and to present their challenges in ways understandable to judges (and bloggers!) who have more limited expertise in quantitative methods.

They did a good job!

This difficult challenge may not have left room for any distractions that come with the bag of tricks that has been used when questioning other plaintiff's expert witnesses. Jack Siemiatycki was spared the mockery and challenges to his judgement and scholarship that were experienced by Robert Proctor, Richard Pollay and André Castonguay.

Instead, most of the day was spent with Guy Pratte leading the witness through a series of finely sequenced questions aimed at getting the epidemiologist to acknowledge that the methodological choices he had made would have affected the reliability of his results.

During the first couple of hours of this effort, I felt like I had accidentally dropped in on an upper-year lecture on statistical methods. Mr. Pratte was at the head of the class, explaining concepts underlying the measurement of differences between studies or the attribution of those differences.  Q value! I squared! 

The pedagogical nature of the exercise was emphasized by the introduction of extracts from text-books, and by the illustrations offered when these concepts were applied to Mr. Siemiatycki's calculations. (Exhibits 40042.1, .... 40042.5)

Mr. Siemiatycki responded very politely throughout this process. He either agreed with Mr. Pratte, or did not let his disagreement get in the way of the groundwork that the lawyer was making. He offered the occasional conceptual reservation, but was quick to express his willingness "for the sake of the argument to along with the idea." 

In less time than a standard university lecture period,  Mr. Pratte had finished the ground work and began to present his central challenge to Mr. Siemiatycki's conclusions: "Would you agree that the extent of heterogeneity would impact the reliability of your summary data [about lung cancer]?"  

Mr. Siemiatycki quite agreeably replied. "As a generic statement, yes," he said, then added "But in particular circumstances it might be moot." 

It was not until some time later (and after a brief flurry of excitement when Mr. Siemiatycki disclosed a calculation error) that the witness began to politely pour cold water on Mr. Pratte's argument.

"There are many reasons why different studies may vary from one to another," he explained. "The most important reasons are probably methodological." 

The issues raised did not affect his overall conclusions, he said. "I became convinced that no matter what level of heterogeneity there might be among the studies, the range of values from all of the studies was so far off the chart for what we usually see in terms of the magnitude of relative risk and dose response relationships, that it would have little impact on the final results."

He outlined in numerical terms the impact that would be felt and then provided a more memorable way to understand the issues. "To answer a question about whether the Himalayas are higher than the Alps, you don’t need the most specific measure possible."

He said that the difference would be at the "margins" of the smoking population, with people who have only a handful of pack-years smoking experience. "All of these arguments ... are trivial because nobody smokes that little."

Mr. Pratte tried to introduce other methodological concerns -- like the failure to include "prediction intervals," or possible differences in the types of cigarettes smoked or the population studied. But these issues were on Mr. Siemiatycki's home turf, and easily rebuffed. With confidence and eloquence, Mr. Siemiatycki defended the appropriateness of drawing inferences in the way he had done.

In the face of such well articulated knowledge, Mr. Pratte was at a disadvantage. He temporarily relied on some lawyerly questions -- "you can't exclude...", "you didn't investigate..." but soon announced that he had no more questions to ask.

There were two other quick rounds of questions from Simon Potter (PMI/Rothmans, Benson and Hedges) and Allan Coleman (Imperial Tobacco), both focused on assumptions of linearity in the models.

At the end of the day, as the plaintiffs' were able to respond to the cross-examination, there were already clear signals from Justice Riordan that he did not need to or want to hear any more. Nonetheless, André Lespérance wanted his witness to clarify some issues.

He focused on the core of the methodological concerns. What if Mr. Siemiatycki approach miscalculated how much someone had to smoke before tobacco use was the likely cause of disease?  What if there were a different "critical amount."?

Mr. Lespérance put it this way: "How critical is the critical amount to the bottom line?"

"Not very critical," replied Mr. Siemiatycki. "Estimates can be made with different models and different assumptions, but once we are in the range of pack years from 2 to 12, we will end up with the same number."  He explained that the vast number of lung cancers were found among people who smoked for 20 or more pack-years. "The average pack years for lung cancer cases is 50."

Nor were other causes of cancer - including asbestos and alcohol - likely to greatly affect his conclusions. "It is like Mount Everest compared to Mount Royal - which one can obscure the other one." 

In the months to come, the epidemiologists and statisticians hired by the companies will present their reports, and Mr. Siemiatycki is expected to again offer his insights at that time. If today is something to go by, it is a day to look forward to.

Tomorrow and Thursday the trial will hear from the plaintiffs last expert witness, Dr. Juan Negrete. He will testify about addiction.

Day 118: Chipping away at the estimated deaths

The cross examination of epidemiologist Jack Siemiatycki at the Montreal tobacco trial continued this morning for less than an hour.

Yesterday, JTI-Macdonald lawyer, Guy Pratte, had pushed for the plaintiff's expert witness to admit that there were other ways of calculating his estimate of the number of Quebecers who had died as a result of four smoking-related diseases, and that these other methods ways would produce a lower total than the one Mr. Siemiatycki had presented to the court.

Today, Mr. Pratte focused on whether the epidemiological model that had been used by Mr. Siemiatycki took into account other factors that might be relevant when deciding any fault on the part of the companies' actions in Quebec.

Did he know whether the cancer patients whose cases were  registered had smoked in Quebec, or whether they might have done their smoking in other parts of the world, and only died in Quebec?  Did his model reflect how much smokers who died knew about the risks of smoking? Whether these smoekrs were influenced or not by the marketing or other actions of the companies?

After Mr. Siemiatycki gave the expected answer that none of this was reflected in his model, Mr. Pratte asked him to acknowledge that these factors also might be considered in any calculation of a "legally attributable fraction" of deaths due to smoking. Mr. Siemiatycki agreed.

The questions put by Mr. Potter, who represents Rothmans, Benson and Hedges, were even briefer. He wanted to establish that the epidemiologist had not had access to any of the data that the plaintiffs might have collected on members of the class action. Mr. Siemiatycki appeared unaware that there was even such a databank, and agreed with Mr. Potter's assertion that he did not know whether "the conclusions [in his] meta-anlaysis jive with what is in their databanks."

The third lawyer to cross-examine this witness was Allan Coleman, who did so on behalf of Imperial Tobacco. This is the first issue managed by Mr. Coleman in this trial and by design or personality he aligned his style with that of the more cordial members of the defence team.

Mr. Coleman returned to two methodological issues that had been discussed yesterday. The first was whether 'pack-years' is the best measurement  for smoking history. The second was whether the dose-response relationship between smoking and cancers and emphysema should be described linearly or in other ways. For both issues, he referred Mr. Siemiatycki to studies he had participated in, or which were prepared by highly reputed epidemiologists (Richard Doll, Richard Peto, Michael Thun).

Mr. Siemiatycki did not deny that other approaches had been suggested, or that there was a "body of evidence" that supported a different measure of smoking history. "One reason there is no consensus", he explained "is because there are different purposes – and the different purposes may suggest differing ways of doing it." 

All questions to Mr. Siemiatycki were suspended at that point. In March, he will return to the trial in order to be cross-examined about his decisions about 'heterogeneity' in his analysis of data.

Hand over the data?!!

A lot of time has been spent during the past week talking about (but never seeing) the response prepared by Mr. Siemiatycki to the epidemiologists hired by the companies to critique his work.

Today, Mr. Lespérance reported that this new analysis would not be presented to the trial until after the industry's consultants had testified, should they be certified as expert witnesses.

Mr. Potter was quick to push for the release as soon as possible of the data on which Mr. Siemiatycki based his report - even before it is certain that this information will be provided to the court.

This is no small request and no trifling matter  -- the companies want access to the data that has been gathered by Mr. Siemiatycki and his colleagues over several years.  The significance to public health of the companies gaining access to this information was not discussed.

The road ahead

Even before Mr. Siemietycki had left the room, Justice Riordan had turned the conversation to trial schedule during the month of April.

A month from today (March 21) the plaintiffs are scheduled to have "finished their proof." Normally, this would be the moment where the tobacco companies would begin their defence - but this trial seems to have its own sense of 'normal.'

The companies are planning a formal request for Justice Riordan to toss out some or all of the allegations against them (their upcoming request is being referred to as "motions of non-lieu"). The judge has done much to pour cold water on the idea, although today he acknowledged that he was 'intellectually curious' to see the reasons behind it.

As if to underline his view that this motion will go nowhere, the judge today pushed to have the trial move ahead during April, as if the motion were not on the horizon. This soon felt like his opening gambit in a scheduling game with the companies that had the feel of a round of championship poker.

While the plaintiffs mostly watched (I think they are not of a strong view whether the trial suspends for a few weeks in April), Justice Riordan countered each of the industry's excuses without making eye contact and without giving ground. Key team members not available in mid April? - then let's schedule for a week earlier! Heavy work load? - then call in another member of your team!

The companies finally signalled that they had received the message that Justice Riordan was "very very hesitant to take a five week break" and undertook to come back on March 4 with a suggestion for "some use we can find for 5 weeks." 

The trial will now take a one-week break and then return  for the last month of the "plaintiffs' proof". It looks like it will be a busy month, with many issues needing resolution. 

Already for the first week there will be new witnesses (Mr. Bilimoria), returning witensses (Mr. LaRiviere), issues to be resolved (market shares of the companies) and lots and lots of new documents. Other witnesses scheduled in March will be William Farone, Juan Negrete, Jeffrey Wigand, Wayne Knox, Christian Bourque and Jack Siemiatycki.

The trial resumes on March 4th. 

Day 117: Trying to shake the Confidence Interval

Today was the first day of the tobacco industry's cross-examination of the plaintiffs' epidemiologist in the trial of the Montreal class action suits.

The companies appear to have learned from their experiences when cross-examining the first few expert witnesses. In November, after a short battle of wits, they quickly threw in the towel when they were unable to best historian Robert Proctor. In January their re-hash of insinuations and insults directed at marketing expert Richard Pollay left the impression of school-yard pugilism more than substantive rebuttal.

But in their response to chemist André Castonguay last week and epidemiologist Jack Siemiatycki today, a new approach is taking shape. Instead of a showy "take-down" or grand reveal of character flaws, the companies now seem aimed at "wearing down" the witness with an onslaught of surprise documents and a series of relentless questions.

The tone has also shifted, and with it the players. The old-style veterans on the tobacco file, Simon Potter and Doug Mitchell, have been moved to the back seats. The Ontario-based counsel for ITL are, for once, sitting quietly. Instead, the limelight has been given to the Quebec members of their teams - Ms. Suzanne Côté (who questioned Mr. Castonguay last week) and Mr. Guy Pratte (who questioned Mr. Siemiatycki today).

If nothing else, their style of substantive steady questions asked in firm-but-polite tones seems better matched to the approach of Justice Riordan.

Bench strength

Although Guy Pratte was the one asking the questions today, it was clear that this was a significant group effort. At his side was Kevin LaRoche, who seemed equally familiar with the questions and where they were heading. More help sat at the rear of the room in the form of hired consultants, additional legal team -- and, it would appear, a visitor from Japan Tobacco's Swiss headquarters.

The pretence of not understanding the science had mostly been thrown off by Mssrs Pratte and LaRoche. Despite taking a pronunciation lesson from the witness over the correct way to say adenocarcinoma (it is not only lawyers who can try to destabilize a verbal opponent!), Mr. Pratte sounded extremely knowledgeable about many of the finer details of this specialty field.  These two men certainly seem to have learned a lot since a few days ago when they said they would not be able to properly represent their client.

The day began with Mr. LaRoche handing over to the plainatiffs and the court officers a CD that contained dozens of documents, none of them known in advance by the witness. This assembled material became the basis for a stream of questions aimed at getting Mr. Siemiatycki to acknowledge that his calculation of the number of Quebecers who had suffered from the four lung diseases that are the subject of the Blais-CQTS case could be an overestimate.

Hacking away at the critical point

Yesterday, Mr. Siemiatycki had explained how he had arrived at the quantity of smoking that was required before a court could presume that it was smoking that caused the disease in question, and not some other factor. Mr. Lespérance had asked a series of questions that allowed him to show how this "critical point" had emerged after a number of logically connected calculations.

Today, Mr. Pratte asked questions that challenged those calculations, and many of the choices Mr. Siemiatycki had made as an inherent part of the epidemiological process.

Why assume the relative risk for smokers for emphysema was the same as for COPD? Why assume a linear dose-response relationship? Why not make separate analyses for each of the lung cancer types? Why use a random effects model instead of a fixed effects model? Why not conduct the same sensitivity analysis for laryngeal cancer and pharyngeal cancer as for lung cancer? Why are other risks for cancer considered multiplicative with risks from smoking, and not additive?

In each case, Mr. Pratte suggested that other choices were available that would have raised the "critical amount" of smoking at which a disease should be linked to tobacco use.

As a seasoned epidemiologist, Mr. Siemiatycki must be used to arguing methodology, and frequently drew on this experience. He carefully refrained from agreeing too readily with statements that were put before him, asking for time to review the whole paper. He was comfortable - and showed it - in talking about the many approaches used in his field, and in the competing views about them. He did not hesitate to agree on the broad lead-up questions, while often (but not always) disappointing Mr. Pratte by not giving him the final answer he was seeking.

It appears Mr. Pratte inhaled

Mr. Pratte repeated an ongoing theme of the defence that population estimates are limited in value and that it  important to know individual smoking histories before coming to any conclusions about any cause of illness.

He artfully used his own smoking history as an example, claiming to have smoked for 10 pack years between the age of 15 and 20. He used his own life to try to show that Mr. Siemiatycki's analysis failed to distinguish between someone like him who was, he maintained. unlikely to become ill from smoking and a more recent quitter.

"Your 10 pack-year history can mean someone who smoked 2 packs a day for 5 years continuously, or someone who packed 1 pack a day for 10 years. It could mean someone who didn't smoke a whole lot, like my mother, who smoked half a pack a day for 20 years. ... If I had an individual person in front of me, I could ask them when they started or when they started and that could make a difference in their risk profile."

"It wouldn't make a huge difference," was the reply.

Herrings (red) and Hetero (geneity).

The one area where Mr. Pratte seemed to make more headway was in his questions to Mr. Siemiatycki about the lack of reference to "heterogeneity" in his analysis, and why reference to this part of the analysis had not been included.

(As I understood it today, if studies are of populations that are too varied, or heterogenous, the results shouldn't be mixed the way that Mr. Siemiatycki had done).

This issue had been included in the criticisms of his report levied by Laurentius Marais. Mr. Siemiatycki appeared ill-prepared to answer these questions today, in part because he had not been directly involved in the mechanics of producing the estimate and in part because "I have not paid attention to Mr. Marais' critiques because I thought they were red herrings."

He said he "would be happy to answer your question, but I would like a bit of time, perhaps a couple of days to think about and reflect and get back to you."  Because of these outstanding questions, Mr. Siemiatycki will return to testify on heterogeneity in March.

Not whether but by how much

If there was a time when tobacco company lawyers cast doubt on the epidemiology that demonstrated that smoking caused lung cancer, it was not echoed in any of the questions put to Mr. Siemiatycki today.

The admissions that Mr. Pratte was trying to wrestle out of Mr Siemiatycki would not have cast doubt on the fact that smoking was responsible for tens of thousands of recent Quebec cancer deaths. They might serve to reduce the estimate, but not by an obviously large amount.

Lots of time today, for example, was spent discussing whether the confidence intervals on estimates of larynx cancer risk should be wider. This would potentially exclude more victims from compensation, but larynx cancers represented less than 2% of the deaths Mr. Siemiatycki counted in his estimate of those "legally attributable" to smoking.

Reflecting on the graphs presented yesterday, it also seems that even if Mr. Pratte succeeded in shifting the slope of the dose-response relationship, or moved the "critical point" over to a higher value, the number of deaths that would be removed from the plaintiffs' case would be very low.

Tomorrow, the cross-examination of Jack Siemiatycki will continue.  

Day 116: Let me draw you a picture

Having watched epidemiologists present their findings to audiences whose math skills do not match their interest in the subject, I was a little concerned that today's appearance by Jack Siemiatycki at the Montreal tobacco trials might serve to confuse as much as enlighten.

Perhaps I took too seriously the suggestions of (JTI-Macdonald lawyers) Kevin LaRoche and Guy Pratte that the content would be too challenging even for their intellectual powers. If they felt they "could not master" the content, what hope would there be for the rest of us?

I was wrong to have any such apprehension.

Facing the prospect of handful of industry experts trying to throw up dust around Mr. Siemiatycki's conclusions, André Lespérance took the wise course of unbundling the report of his renowned expert witness, and allowing him to demystify it.

As it turned out, the key conclusions of Mr. Siemiatycki's expert report (Exhibit 1426.1) were not discussed today, at least not in terms of the numbers he finally arrived at.  (He concludes that there were 110,000 Quebec residents in the class period whose "who suffered from one of the four diseases and who would have had probability of causation greater than 50% that the cause was cigarettes smoking.")

Instead, what was presented was how he arrived at this conclusion, and why any other approach should bring the court to a similar finding.

iCourt

The risk of this approach could have been the glazing of eyes and later confusion. It was the manner of presentation chosen by the plaintiffs, however, that made the exercise simple, clear and compelling.

A few weeks back André Lespérance had suggested allowing Mr. Siemiatycki to illustrate his ideas using Powerpoint. The idea had been shot down, including by Justice Riordan, who said it was "looking for trouble" to bring new material to court in this way because of the objections it would trigger.

So the plaintiffs ingeniously hit upon another technology - the iPad app "Paper". Despite a few technical rough spots, this had the apparent spontaneity of a back-of-the-envelope sketch, while leaving a document for the court record. Better yet, the opposing lawyers seemed happy with the idea, or at least unprepared to challenge it.

Continuing Education

iPad at his fingertips, Mr.Siemiatycki resumed his gently-paced tutorial from the day before, when the concept of relative risk had been presented. He began today by explaining how to estimate the amount of disease that can be attributed to risk exposure (attributable fraction).

He related the concept to the job at hand: "You have in front of you a certain number of cases [of cancer] that have occurred in Quebec and the natural question is 'what fraction of these would not have occurred but for smoking?' – it is the Attributable Fraction among the Population that answers that question." 

He showed how to estimate the amount of cancer among all smokers and former smokers that could be attributed to smoking by measuring the area/number of people that lay above the normal risk that existed for smokers and non-smokers alike. The Attributable Fraction (AF) area is shown with black diagonal lines.

He also showed an alternative way of viewing it if smokers were divided into categories of risks  depending on how long or how much they had smoked. This area (shown with yellow diagonal lines) hinted at what was to come next. (I added the  typed descriptions of smoking patterns because these were only given orally).

The second concept he presented today was the probability of causation. "When a person is selected at random ...  he is sick, and he is a smoker and we know nothing else about him. how can we guess at the probability that his disease was caused by smoking?" he asked rhetorically before providing his answer. "The best approach is to look at the attributable fraction [and determine] what is the probability that he will be chosen from above the dotted line or below the dotted line [that separates the normal risk from the additional risk]." 


Again he used the iPad to illustrate an equation by which the probability of causation could be calculated. He described it as the additional risk divided by the whole risk, or PC=(RR-1)/RR.

By way of example, the probability of causation if the relative risk were 10 would be (10-1)/10, or 90%. The probability of causation if the relative risk were 2 would be (2-1)/2 or 50%.

Up to this point, he said, he had presented  "conventional" ideas within epidemiology. The the next concept, however, was one of his own characterization.

Legally Attributable Fraction 

He said he had wanted to apply the legal concept of balance of probabilities to the epidemiological notion of probability of causation. "The way I thought about the problem was this “cut point” where something is more likely than not ...greater than 50% probability."

He gave this quantity a name - the Legally Attributable Fraction (LAF). There was clearly some discomfort in the court with  the term 'legal' being bandied about by a scientist (Simon Potter registered an objection and Justice Riordan found alternative ways of expressing it), but the construct continued to be used by the witness throughout the day.

Mr. Siemiatycki explained that in a group where the probability of causation was less than 50%, none of the disease would be considered a "legally attributed fraction." In a population where  the probability of causation was higher than 50%, however, everyone would be included.

On Exhibit 1427.3, with a hypothetical probability of causation drawn underneath categories of smokers with increasing levels of cigarette exposure, he drew the LAF in red lines (all those with the probability of causation over 50%). The proportion of disease that would be not be considered to be legally attributable was drawn in grey lines (probability of causation less than 50%).

Every former student of calculus will be familiar with his next move -- translating the discrete steps into a continuous sloped line that represented the dose response risk. The more you smoke, the greater the risk - not in discrete lumps but in a smooth continuous way. Based on his review of several studies, he calculated that the slope of this dose-response line was .34, and that every additional pack year increased the relative risk of lung cancer by .34.

He defined a "Critical point [C] where the probability of causation hits 50%," and pointed out that mathematically "that corresponds to the level where the relative risk is equal to 2."  This is the amount of cigarette consumption at which a cancer patient can be thought, on a balance of probabilities, to have had his or her cancer caused by smoking.

The next building block in this exercise was to determine how many cigarettes someone would have to smoke for the relative risk to be equal to 2. His meta-analysis had suggested that for lung cancer, this would be 4 pack-years for men and 3 pack-years for women. (For larynx cancer, throat cancer and COPD/emphysema it was slightly higher, at about 5 pack-years).

No mathematical mystery. No fancy footwork. No voodoo. Just simple ideas, simply presented.

The bigger picture

At this point the lecture broke for lunch, and when the session resumed in the afternoon, André Lespérance moved to questions that involved somewhat more detailed explanations, and which laid the foundation for Mr. Siemiatycki's final explanations of why it is that even if the values underlying his calculation were adjusted somewhat, the general conclusions would not change greatly. In some detail, he showed how his calculations understated the number of cancers caused by smoking.

Mr. Semiatycki's professional life usually focuses on risks other than smoking, but nonetheless he recognzies tobacco use as a predominant risk for disease in Quebec. It is the double-whammy of a higher risk combined with greater population exposure that has put tobacco in a class of its own. "There is really no comparison in the magnitude of the impact they can have. One [tobacco] is enormous and the others [occupational and environmental exposure] beside it are small." 

The defence teams sit it out.

There were very few objections voiced today by any of the three defence teams.

Guy Pratte had been given the lead with this witness, and at one moment he tried to object to the introduction of term "legally acceptable fraction" that had not been used in Mr. Siemiatycki's 2009 report but which had, apparently, been used in the more recent version which has not been filed with the court.

Justice Riordan seemed satisfied that the elements of the idea were in the 2009 report and allowed the new concept to be discussed. This sounded like a significant set-back for the defence, particularly in light of the prominent role that this argument had taken in their sabre-rattling last week and yesterday.

We will find out tomorrow, when Jack Siemiatycki will be cross-examined. I think the risk that he might be allowed to use an iPad to illustrate his points is relatively small.

The cross-examination of Jack Siemiatycki is scheduled for tomorrow and Thursday.

Day 115: Jack Siemiatycki's "bald brutal facts"

For information on accessing documents, see note at the end of this post
It was a very expensive day for the tobacco companies who are defending against two class action lawsuits in Montreal. The plaintiffs had another star expert witness - epidemiologist, Jack Siemiatycki - and to counter his impact, the defense teams had brought out the high-priced help.

In addition to the 'team captains' that were on hand (Guy Pratte for JTI-Macdonald, for example, is an uncommon presence in court), the benches were strengthened with the specialty players, like Kevin LaRoche who seems to act as JTI-Macdonald's science guy. Even the public benches looked a little full, thanks to the presence of the industry's own team of experts who had flown in from the United States. Notebooks in hand, they sat with their handlers and watched closely, occasionally conferring.

The subject matter of Jack Siemiatycki's expert testimony would be enough to rouse the companies to an energetic defense, as it cuts to the core of the lawsuit. His job, as he describes it in his report (Exhibit 1426), was to "provide evidence and expert opinion regarding the causal links between cigarette smoking and each of four diseases [that are the subject of the Blais-CQTS case]: lung cancer; larynx cancer; throat cancer; and emphysema."

The efforts to blunt the conclusions of witness had started many years ago. Justice Riordan greeted him this morning by remarking on the large number of (contentious) discussions over the past five years that had involved his name.

Introducing Mr. Siemiatycki


Epidemiologist
Jack Siemiatycki

As André Lespérance guided Mr. Siemiatycki through some highlights in his CV, (Exhibit 1426.1), it became clear that this was a witness with a professional standing that could only strengthen his conclusions.
Mr. Siemiatycki (Ph.D in epidemiology and medical statistics) has cross appointments in Montreal's universities and has participated in key cancer research at IARC, and other government and inter-governmental research endeavours.

In addition to a publication record that is lengthy and cited (he boasts the highest ranking among public health researchers for publication impact), Mr. Siemiatycki is involved in some of the most ambitious epidemiological reviews, and sits on numerous scientifically prestigious committees.

It is not only scientists who value his work. His credentials have previously been recognized in Quebec courts, when he assisted the federal government in defeating a class action related to contaminated water near the Valcartier military, and helped Alcan fight back claims that its workers' lung cancers were caused by workplace exposure.
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So when it was Guy Pratte's turn to question his qualifications on behalf of the tobacco companies, it was not surprising that he chose against trying to dispute the credentials of this well-reputed scientist. Perhaps also he recognized that it might not be so smart for someone from a corporate law-firm to lessen the value of someone who might later be needed on the "defendant" side of the courtroom.

As a result, Mr. Siemiatycki did not have to endure the attempts that have been made to belittle or discredit other witnesses. Nor was he asked whether he had "joined the religion" against tobacco.

Instead Mr. Pratte wanted to know about the background to the reports he had prepared in 2006, revised in 2009 and then corrected in a 2012 report that had been circulated among the lawyers, but which Justice Riordan had ruled last week would not be presented to the court.

Mr. Pratte normally projects enormous self-confidence, so it was a little odd to hear his repeated references to inadequacies in his understanding of science and statistics. Acting might be a part of the practice of law, but acting dumb is not part of the usual repertoire in this courtroom.

After guiding the witness around the field for a bit, Mr. Pratte took him to what was clearly the main point -- the collection of smoking histories as part of a "Montreal 2" case control study. This data was collected from 1996 to 2001 and included information on smoking histories and lung cancer. It had been cited in other reports produced by Mr. Siemiatycki's research team, and Mr. Pratte wanted to know why it had not been used in the 2009 report.

Mr. Siemiatycki"s explanation seemed disarmingly frank. It wasn't his choice, he said, but was decided for him by the plaintiff's lawyers. "The instructions I had in 2009 when I revised the report were 'don’t change anything fundamental, because if you do the other side will scream blue murder'."  With so many studies on lung cancer and smoking, a meta-analysis was a "moving target" he explained.  He had been told to respect the 2005 "cut point."

Mr. Pratte continued to focus on the research and not the qualifications, as did Simon Potter and Allan Coleman later in the morning. The witness seemed genuinely perplexed by this line of inquiry. "Is this germane to whether I am an epidemiologist?" he asked, before being reminded by the judge to "please just answer the question"

He explained why he had shifted his analysis from the use Statistics Canada data to establish smoking history to the use of data from the "Montreal 2" study. "After I reviewed the critics' comments and saw that they were questioning the method I had developed, which I thought was clever but they didn’t,... I thought that if they want to question the use of the Statistics Canada data and how I transformed it, I have a better way to do it." 

As for the timing and why the new version was circulated so late in the game? "I have a day job that keeps me pretty busy and it was probably around spring of 2012 that I got around to focusing my attention on the criticisms and trying to think of how to accommodate them."

Not the messenger, but the message.

The companies finished their questions on Mr. Siemiatycki's qualifications just before lunch time, and the court recessed without any indication of whether they would formally contest his qualifications. When the session resumed, it became clear that the the concerns of last week were going to be re-hashed.

Simon Potter gave the first push. The witness might be qualified, he said, but the plaintiffs had contaminated the process. "Even if the witness is qualified and an expert in his particular field and even if in the normal way you would move ahead, the judge should use judicial discretion and not push forward down the path which is firstly perfectly unfair and secondly a manipulated path created by the attorneys on the other side."

After a few minutes, Justice Riordan begins to look impatient. "Didn’t I deal with this last week?" he asked. "Maybe we weren’t in the same place this morning – I am not following your arguments at all." 

Undeterred, Mr. Potter repeated his concern that the witness' corrections to his report, even if they were not formally before the court, had changed the situation. "As soon as we get into the criticisms [by the industry experts of Mr. Siemiatycki's report], which he is entitled to do ... it will be untenable for us to know what he is talking about if we don’t have the information." 

Justice Riordan reminded him that he had not only ruled on the topic, he "took the care of copying out and giving it to you. What’s your problem?!"

Guy Pratte gave it a try, asking for a "suspension" of a few weeks or months. He presented the same concern that his colleague, Kevin LaRoche, had tried last week that he would not be able to do his job properly unless they were given more time. (Kevin LaRoche had said he would have to report himself to the Law Society!)

Mr. Pratte's earlier claim to not understand the science was brought into play. "There are all these fomulas! Legally attributable fractions! and relative risks! I cannot master that in a week without the data," he protested. He did his best to sound like a math-hating Barbie, but if there is one thing that Mr. Pratte does not do competently, it is looking incompetent.

I think Mr. Coleman's additional short comments fell on deaf ears. As ITL's lawyer was speaking,  Justice Riordan was focused on his computer. A moment or two later, he read a statement from his laptop that reaffirmed his decision that the testimony would go forward. He sounded quite annoyed..

And so it was that shortly before 3:00 p.m., Justice Riordan recognized Mr. Siemiatycki as an expert in the following areas: epidemiology, epidemiological methods, cancer epidemiology, cancer etiology and lifestyle risk factors for disease and Mr. Lespérance began to ask his witness some questions.

Epidemiology 101

Mr. Siemiatycki was asked to explain some of the basics behind epidemiology -- how it had evolved (recently) as a discipline, what cohort studies aren and how prospective and retrospective cohort studies differ.

He stressed the "observational" nature of this science, and reminded the court of the health breakthroughs that had come as a result of this type of researcher. Fluoride and dental caries. Exercise and improvements in heart disease. HIV/AIDS and sexual transmission.

"There are huge benefits of epidemiological research that are put into every day life," he said, stressing that epidemiology allowed for health interventions before the biological underpinning of some diseases were understood.

From the beginning of his studies in the late 1960s, the link between lung cancer and smoking was held up as a model case study for epidemiological research. He explained that the Surgeon General's findings in 1964 that "average male smokers of cigarettes have approximately a 9 to 10 fold risk of developing lung cancer and heavy smokers have at least a 20 fold risk” had been based on pooled data from studies available at that time, although the term meta-analysis had not yet been coined. His own research on the Montreal 1 cohort study (Exhibit 1428) had produced similar results.

Gradually the questions and answers became a little more detailed. Mr. Siemiatycki tried to explain how confidence intervals were calculated (by computer programs, it would seem). His description of relative risk was made clearer by the novel use of the popular ipod "Paper" app. (If the defendants don't want Powerpoint - give them Paper!) He illustrated the need to control for confounding factors by pointing to the apparent higher death rate in Victoria than Shawinigan if the data is not "adjusted for age."

This first round of questions in the last part of the day felt like the warm-up to more substantive questions tomorrow.

Mr. Siemiatycki is scheduled to testify throughout the week.


The documents are on the web-site maintained by the Plaintiff's lawyers. To access them, it is necessary to gain entry to the web-site. Fortunately, this is easy to do. 

Step 1: Click on: https://tobacco.asp.visard.ca

Step 2: Click on the blue bar on the splash-page "Acces direct a l'information/direct access to information" You will then be taken to the document data base.

Step 3: Return to this blog - and click on any links.

Day 112: How many epidemiologists does it take to change a light bulb?

Six.  One to change the bulb and five to critique the method.


For information on accessing documents, see note at the end of this post

There was a lot of unintended humour in this morning's discussion about the forthcoming testimony of noted McGill epidemiologist, Jack Siemiatycki, at the Montreal tobacco trials.

This discussion came in lieu of Dr. Guertin's testimony, which had ended a day earlier than expected.  (Is it a courtroom application of Parkinson's law that arguments expand to fill the time available?) The key question under debate was whether Mr. Siemiatycki should be allowed to testify as scheduled next week.

Mr. Siemiatycki had been engaged by the plaintiffs to give an epidemiological review of the four diseases covered by the Blais-CQTS lawsuit and to estimate the numbers of Quebecers affected. (For those who don't like suspense, his answer is that "from 1995 to 2006, there were 110,282 Quebec residents who suffered from one of the four diseases and who would have had probability of causation greater than 50% that the cause was cigarette smoking.")

Click to enlarge - Siemiatycki estimates 

His long expert report, written in 2009, makes clear that he did not pull those numbers from a hat. He supports his findings with 50 pages of descriptive analysis and 33 pages of tables. To this belt of method, he then adds the suspenders of a 97-page appendix of previous epidemiological reviews.

But rather than settling the matter, these 200 pages of research material provided fodder for criticism from willing hands engaged by the tobacco companies. (Links to critiques of the industry witnesses are at the end of this post).

Five US-based consultants had criticized, among other things, the studies that had been included or excluded from Mr. Siemietycki's analysis, the approach he took to estimating smoking histories, and the absence of a way of distinguishing between diseases that had been caused by wrongful tobacco marketing and those that had resulted from fault-free marketing. In addition to these concerns, there are many many complaints about epidemiological methodology that are lost on me.


Damned if you do.  Probably damned if you don't. 

A comprehensive response by Mr. Siemiatycki to these criticisms was clearly no small task.

About a month ago, Mr. André Lespérance informed the court that his expert had indeed prepared a response to his critics, and that this reply involved some new data. He undertook to provide the information by this week (February 8-11), and sought guidance on whether a powerpoint presentation could be used as a tool to simplify the communication of his response. (There was no wide agreement on the use of powerpoint, which seems a pity given the state of science literacy in Courtroom 17.09).

The material was apparently circulated last Friday, as promised, and the reaction was fast and furious. Each of the companies' lawyers was in high dudgeon this morning about the length of the additional material (102-pages), the length of time that had elapsed since their criticisms were levelled and the response was circulated (two years), and the inclusion of new material - even when new material had been demanded by the critics.

Before the session opened, Mr. Lespérance was seemingly trying to persuade the other side to come to an agreement on how to proceed, but to no avail. With three angry opponents threatening to block next week's testimony, he rose at the beginning of the session to present the issue to Justice Riordan and to propose three options to manage opposition. Each of these proposals would have deferred all or portions of Mr. Siemiatycki's testimony.

Jaws dropped when Justice Riordan raised the offer for the plaintiffs before discussions began. "I see a fourth option," he said. "We could do it as foreseen, and I will hear objections and rule on them at the time." At this comment from the bench, faces on the plaintiff's side relaxed (I am sure I saw a "thumbs up!" signal pass among them), and the lawyers for the defendant companies stiffened in their seats.

Simon Potter (RBH) was the first to detail his objections. With his trademark drama he waved the new report in the air (Justice Riordan decline the offer of a copy). His major complaint seemed to be that Mr. Siemiatycki had done the work his critics suggested. 

"Included is a huge piece of work done by Siemiatycki himself! ...  The new report is replete with the words corrected or revised ... Instead of responding to criticism by saying he didn’t have to [make the changes his critics demanded], he has now put in a massive amount of work...."

Kevin LaRoche (JTI-Macdonald) who is an infrequent presence in this courtroom, was less over-the-top in vocal mannerisms but no less melodramatic in his objections. "Not only do the [industry] experts need time, but I need time. The suggestion that this gentleman should be able to stand up next week is inconceivable to me." 

How dire was it in Mr. LaRoche's view? Bad enough to call in the benchers and report himself for not being able to represent his client!

"I should have to call up the Law Society and report myself... "I am not in a position to understand the information ... I wouldn’t know what to object to. ... It's just not on!"  (This was only one of the moments this morning when I was grateful to be sitting at the back and not obliged to keep a straight face)

Imperial Tobacco had dug deeper into its talent bank, and today introduced yet another Osler Partner from Toronto to the case. Mr. Allan Coleman, in the face of some gentle-but-pointed ragging from Justice Riordan over his unfamiliarity with Quebec court manners, clearly and politely presented his arguments that the companies should be able to review the data behind the response.

When he began his reply to these concerns, André Lespérance made the mistake of referring to past grievances about the conflicting experts not being allowed to meet face to face. Justice Riordan has no appetite for whingeing, and this provoked a sternly-toned reprimand from the bench: "The debate is not because of the absence of a discussion, but because you want to present something new. I warned you that you were opening the door to problems." 

Mr. Lespérance got quickly back on track and explained that that his expert had done as he should have done by responding to the criticisms, by doing further work, and by making the details of this work available in advance. He pointed out that an expert witness was entitled to respond to criticisms. If the additional work was not appreciated, so be it. "We can live with his first report."

Justice Riordan came back to his starting point that next week "should follow the normal procedure."

Simon Potter tried to persuade him that it was hard to go back -  "the toothpaste is out of the tube" - but seemed to realize that he was fighting a losing battle. "I will sit down before I make things worse," he said. And did.
.
Before calling a pause to go and write out his decision, Justice Riordan reflected "I see this as something of a tempest in a teapot ... Science shouldn’t be as controversial as it seems to be here."  Perhaps he has never met an epidemiologist.

His decision was foreshadowed in the faces of the legal teams as they waited for him to come back with a ruling. The plaintiffs were smiling, and chatted freely as they went down for coffee. The defendants gathered tightly for a hushed conversation.

His ruling was yet another example of his determination to keep this trial rolling and his desire to limit the "replies to replies" between experts.

Next week Mr. Siemiatycki will testify, as scheduled, on his 2009 report, as well as on his response to the criticisms of it. The plaintiffs may seek permission to file other material to support his opinion, but not the new report that was circulated. Within a defined timeframe, the defendants can ask for background information, call Mr. Siemiatycki back for a limited further cross-examination, and offer one response from an expert who has met with Mr. Siemiatycki.

Jack Siemiatycki's critics.

The companies have hired the following experts to provide responses to Mr. Siemiatycki's report.

Kenneth Mundt. His 27 page report offers wide-ranging criticism of Mr. Siemiatycki's analysis, without providing any estimates of its own.

Laurentius Marais.  He derides what he calls "opinion-based estimates" in his 124 page detailed critique,

Dr. Sanford Barsky He includes in his rebuttal to Dr. Alain Desjardain's opinion some criticisms of Mr. Siemiaticki's findings.

Dr. Dale Rice. He who similarly includes criticisms of Mr. Siemiaticki's findings in his rebuttal to Dr. Louis Guertin's expert opinion.

Mr. Bertram Price. He provides a competing analytical framework and proposes a different method for linking smoking, wrongful behaviour by companies, and disease.

The rest of the day ...

.... was devoted to tabling documents that had been made receivable as a result of Justice Riordan's "2870" judgements (now before the Court of Appeal), and some that were being filed under the umbrella of his "May 2" judgement. There were scores - maybe a hundred - of these documents.  More on them in future posts.

Tomorrow, two witnesses will be present. The cross examination of André Castonguay will continue (and likely end). Mr. Wayne Knox, a former marketer with Imperial Tobacco, will make his first appearance.

The documents are on the web-site maintained by the Plaintiff's lawyers. To access them, it is necessary to gain entry to the web-site. Fortunately, this is easy to do. 

Step 1: Click on: https://tobacco.asp.visard.ca

Step 2: Click on the blue bar on the splash-page "Acces direct a l'information/direct access to information" You will then be taken to the document data base.

Step 3: Return to this blog - and click on any links.