Lessons Along the Way

https://betakit.com/startupcfo-explains-the-long-windy-road-to-a-closed-funding-round/
 
 
With summer almost here, it’s a good time to reflect on lessons learned from the academic year gone by. Since September, I’ve been working under Dr. Pascal Tyrrell’s supervision on a systematic review (SR) project investigating sample size determination methods (SSDMs) in machine learning (ML) applied to medical imaging. Shout out to the Department of Statistical Sciences where I completed my independent studies course! Here, I share important lessons I learned in the hopes that they may resonate with you.
 
Despite being a stats student (as you know from my previous posts!), I was initially new to ML and confronted with the task of critically reviewing theoretically-dense primary articles. I came to appreciate the first step was to develop a solid background – starting from high-level YouTube videos and lessons on DataCamp, to reading ML blogs and
review articles – all until I was confident enough to evaluate articles on my own. For me, the key to learning a complex subject was to build on foundational concepts and keep things as clear as possible. As Einstein once said: “If you can’t explain it simply, you don’t understand it well enough”.
 
Next, it was time to conduct a systematic search. The University of Toronto library staff were especially helpful at guiding me in use of OVID Medline and Embase, databases with methodical search procedures and a careful search syntax relying on various operators. To be thorough, we also sent a request out to the rest of our research team, who hand-searched through their own stash of literature. Along the way, we garnered support from the university, successfully receiving the Undergraduate Research
Fund grant. The lessons for me here? The importance of seeking expert help where appropriate, and that being resourceful can pay off (literally)! Finally, I valued our strong team culture, without which none of this would have been possible.
 
While working on the SR, I also conducted a subsampling experiment using a medical imaging dataset, testing the effect of class imbalance on a classifier’s performance. Hands-on/practical experiences are critical in developing a more nuanced understanding of subject material – in my case, an understanding that translated to my SR.
 
So now you are probably wondering about the results! The subsampling experiment helped us develop a model for the deleterious effect of class imbalance on classification accuracy and demonstrated that this effect was sensitive to total sample size. Meanwhile in our SR, we observed great variability in SSDMs and model assessment measures, calling for the need to standardize reporting practices.
 
That was a whirlwind recap of the year and I hope some of the lessons I learned resonate with you!
 
See you in the
blogosphere,
 
Indranil Balki
 
A special thanks to Dr. Pascal Tyrrell, as well as Dr.
Afsaneh Amirabadi & Team

A Medical Ethics ROP Journey with Jayun Bae

Jayun Bae – ROP299Y 2016-17
My name is Jayun Bae and I am completing my second year in the Neuroscience and Bioethics majors at the University of Toronto, St. George. I was a 2016-2017 Research Opportunity Program (ROP) student in Dr. Pascal Tyrrell’s lab, working on a study that investigated the ethics of sharing patient data with private organizations (see my timeline above). I am a member of the Hart House Debating Club and an events associate for the Life Science Student Network. 
                                                               
My ROP project was necessitated by the partnership proposed by the Medical image Networking Enterprise (MiNE) that would establish a data-sharing relationship between public and private sector organizations. The ethical concerns with the partnership involved patient consent, privacy, and financial gain – but there were also issues that I
uncovered throughout the project. It quickly became clear that the answers could not be found through an examination of precedence or legal documents, because many of the research actions that would take place (specifically involving private organizations) fell in the grey area between what was legal and what was ethical. For example, the Personal Information Protection and Electronic Documents Act (PIPEDA) and Personal Health Information Protection Act (PHIPA) are two guidelines for organizations to follow when handling patient data – but neither are able to clearly and positively dictate how this partnership should operate.
Therefore, I developed a study that would seek expert opinions through the administration of a survey. I conducted interviews at Sunnybrook Health Sciences Centre and the University of Toronto and performed qualitative data analysis. My ROP project was presented at the ROP Poster Fair and the Victoria College Research Day events. The ROP was an extremely valuable experience in gaining research skills, and I’m grateful to
Dr. Tyrrell for the guidance and mentorship. The project is not yet completed, so I am looking forward to continuing the study beyond the scope of the ROP.   
Please have a look at my poster from the 2017 ROP Research Day below:

MRI, Statistics, Carotid Arteries, and 1000 Cups of Coffee with George Wang

GeorgeWang – ROP299Y 2016-17
I’m George. I have recently completed my 2nd year undergrad at the University of Toronto studying physiology and physics. In the fall-winter term of 2016-17 I had the privilege to work in Pascal’s group, looking into carotid artery MRI and using the volume of the carotid artery vessel wall as a marker for atherosclerosis. Having an acquired interest in medical imaging and a previous summer position working with PET, I saw this as an excellent opportunity to expand my knowledge of the field while having the chance to be exposed to clinical research methods. Above is my account of how the year went in a nutshell.
 
Have a look at my poster from the ROP Research Day below…
 
 

Prison Experiments and Causality? Whoops!

Guard or inmate? Who would you like to be?

In my most recent set of posts I have been talking about Bradford Hill’s criteria for causality (see here for first post). So far we have covered strength, consistency, specificity, temporality, dose-response, plausibility, and coherence. Today we are going to talk about experiment – the eighth criterion. 


This is an easy one (and it’s a Friday… Perfect!). Can the condition of the association of interest be altered (prevented or ameliorated) by an appropriate experimental / semi-experimental regimen? If so, then this would lend support to the notion of causality. 


That’s it. Now consider the infamous Stanford Prison Experiment that has etched its place in history, as a notorious example of the unexpected effects that can occur when psychological experiments into human nature are performed.The experiment was a study of the psychological effects of becoming a prisoner or prison guard. The experiment was conducted at Stanford University on August 14–20, 1971, by a team of researchers led by psychology professor Philip Zimbardo using college students. Needless to say the experiment got out of hand and participants were harmed in the research process. Whoops! Not good.


The Stanford Prison Experiment led to the implementation of rules to preclude any harmful treatment of participants. Before they’re implemented, human studies must now undergo an extensive review by an research ethics board or institutional review board.

 

You may be able to show causality by an experimental regimen but at what cost? Be careful and think about research ethics before you leap into an experiment.

 

Watch the trailer to the movie about the Stanford Prison Experiment to get a better idea of what I am talking about and…


… I’ll see you in the blogosphere!




Pascal Tyrrell

Coherence, Causality… and Space – Time?

Warp speed ahead!

In my most recent set of posts I have been talking about Bradford Hill’s criteria for causality (see here for first post). So far we have covered strengthconsistencyspecificitytemporality, dose-response, and plausibility. Today we are going to talk about Coherence – the seventh criterion. 


The association should be compatible with existing theory and knowledge.  In other words, it is necessary to evaluate claims of causality within the context of the current state of knowledge. What concessions do we have to make in order to accept a particular claim of causality? Too much, too little, or just right?









As with the issue of plausibility, research that disagrees with established theory and knowledge are not automatically false.  They may, in fact, force a reconsideration of accepted beliefs and principles.

In his Special Theory of Relativity, Einstein states two postulates:


1- The speed of light (about 300,000,000 meters per second) is the same for all observers, whether or not they’re moving.


2- Anyone moving at a constant speed should observe the same physical laws.


Putting these two ideas together, Einstein realized that space and time are relative — an object in motion actually experiences time at a slower rate than one at rest. Although this may seem absurd to us, we travel incredibly slow when compared to the speed of light, so we don’t notice the hands on our watches ticking slower when we’re running or traveling on an airplane. Scientists have actually proved this phenomenon by sending atomic clocks up with high-speed rocket ships. They returned to Earth slightly behind the clocks on the ground. 


Not convinced? Watch Einstein’s Time is an Illusion for addtitional insight.


Still not convinced? That’s OK. Often fundamental changes to basic concepts of a scientific discipline take time for people to understand and adopt as a belief. This is referred to a paradigm shift


Bottom line is that the cause-and-effect interpretation of your data should not seriously conflict with the generally known facts of the base of knowledge in your field of study – but there is wiggle room here!




Watch the movie trailer for Coherence to confuse you even more and…


… I’ll see you in the blogosphere.




Pascal Tyrrell

Plausibility, My Dear Watson!

Or was that “Elementary, my dear Watson”? I always get those confused…


Anyway, in my most recent set of posts I have been talking about Bradford Hill’s criteria for causality (see here for first post). So far we have covered strength, consistency, specificity, temporality, and dose-response. Today we are going to talk about plausibility – the sixth criterion. An easy one at that.


For plausibility to exist we need the association of interest to agree with currently accepted understanding of pathological/ biological/ physical processes. In other words, there needs to be some theoretical basis for the association we are considering. While we hope to avoid spurious associations, at the same time, relationships that disagree with current understanding is not necessarily false; they may, in fact, be a needed challenge to accepted beliefs and principles.


 As Sherlock Holmes advised Dr. Watson, ‘when you have eliminated the impossible, whatever remains, however improbable, must be the truth.’


Next time we will talk about the 7th of nine criteria: coherence.




Don’t remember who Sherlock Holmes is? See the trailer to Robert Downey‘s rendition of Sir Arthur Conan Doyle‘s famous detective here and…




… I’ll see you in the blogosphere,


Pascal Tyrrell





A Spoonful of Sugar… Makes the Dose-Response Go Around?

An oldie but a goodie! Haven’t heard of Mary Poppins or her spoonful of sugar? Have a peek here for your dose of the classics. In my most recent set of posts I have been talking about Bradford Hill’s criteria for causality. So far we have covered strength, consistency, specificity, and temporality. Today we are going to talk about biologic gradient or dose-response.


This criterion is pretty easy to understand. An increasing amount of exposure increases a risk in question and with a dose-response relationship present, it is strong evidence for a causal relationship!  


Let’s say you think that being out in the sun in a bathing suit causes your skin to suffer a sunburn. So, the exposure is sunlight and the outcome is sunburn. Based on everyone’s experience, it would certainly appear that the longer you stay out in the sun the greater the risk you will suffer a burn! Your parents have been warning you of this for ever.



However, as with specificity, the absence of a dose-response relationship does not rule out a causal relationship.  A threshold may exist above which a causal relationship is present.  


Next time we will talk about the 6th criterion: plausibility.




Watch one of Simon’s Cat earlier clips Cat-Man-Do and see if you can spot the dose-response…


… and I’ll see you in the blogosphere.




Pascal Tyrrell


All the World’s a Stage

For journalists, authors, bloggers and tweeters, sharing articles has never been easier. Indeed, the public expects to be able to read articles about world events almost in real-time. For example,
the New York Times Twitter account was updated nine minutes ago
, and National Geographic tweeted three minutes ago. This expectation of speediness applies equally to scientific advances as it does to international affairs.
As an avid reader of online news, I would be the last to complain about being able to access such a vast amount of information. But there is something particularly noteworthy about information presented by a visible human. Perhaps that explains the persistence of televised news in the age of Twitter. 

Maybe it also explains the popularity of other media sources like TED talks, which often explain complex ideas in an engaging and understandable format. A personal favourite is “The best stats you’ve ever seen” by Hans Rosling. In his talk, Rosling explains the importance of little-known global public health data that shows the progress (or lack thereof) made by different countries over the past few decades. 

A more recent talk on a similar topic is also informative. One would be hard-pressed to find a paper or article that presents the same information with as much clarity and appeal.

In addition to numerous (maybe too numerous?!) TED talks, I have recently experienced the value of human-to-human information transfer. At the beginning of my ROP project in September, I was lucky to be able to hear about previous students’ research in person. I think it helped address the complexity of the work, but also conveyed its importance and the effort that had gone into it. Thanks Kiersten!
I’m not sure if information is generally more effective this way, but it is almost certainly more memorable. In any case, it has definitely worked for the 3.5 million subscribers to CrashCourse’s YouTube channel, where one can learn about anything from astronomy to macroeconomics.
For me, learning more about how researchers give and receive qualitative information to and from their subjects has allowed for a more well-rounded understanding of information transmission in the digital age.  But I think researchers andthe media have a lot to learn from each other. Communication is key for both, so understanding how others best absorb and respond to information can be instrumental.
That’s all for now, Julia!

Dem Bones Dem Bones Dem Dry Bones

Happy Canadian Thanksgiving!!!

A traditional holiday – originating from the native peoples of the Americas – to celebrate the completion and bounty of the harvest.

This year I am off to Algonquin park for a canoe portage trip with the kids! I will take the time to appreciate some of the successes of our MiVIP program and this blog over the long weekend.

Thanks for being a part of it!

Listen to Dem Bones by the famous Delta Rhythm Boys

… and I’ll see you in the blogosphere.

Pascal Tyrrell

Just in the Nick of Time… Causality.

Now that was a great movie: Interstellar. See the trailer here for a refresher. So this movie talked a lot about worm holes – essentially an area of warped spacetime. Theoretically a worm hole could allow time travel. Want to know more? Grab a large coffee and see here. You may be thinking what all this has to do with medical imaging but, believe it or not, I posted about x-rays in space earlier in the blog (see here).

Listen to Hans Zimmer’s – Time from the movie Inception (another great movie) to get into the mood.

Now, we have been talking about Bradford Hill’s criteria for causality and today we are addressing the fourth one: temporality. The exposure of your association of interest should always precede in time the outcome.  If factor “A” is believed to cause a disease,  then factor “A” must necessarily always precede the occurrence of the disease. So for example the act of smoking (or being exposed to second-hand smoke) must precede the development of lung cancer for the relationship to be considered causal. This is the only absolutely essential criterion (out of nine).

Easy one, right? Next time I will be talking about biological gradient.


I am not sure you need time to decompress today as it has not been too taxing… but listen to Bonnie Raitt Nick of Time anyway…

… and I’ll see you in the blogosphere.

Pascal Tyrrell