Robert Frykberg, DPM, MPH PRESENT RI Editor Diabetic Limb Salvage

Why We Need to Understand Statistics in
Order to be Good Doctors

As Podiatrists, I believe that we start our careers at a disadvantage.  Not because of a lack of talent, intellect, or years of education. To the contrary, I have seen many very talented and bright students come through our clinics over the years.  When we are lucky enough to secure them as Residents, these impressions are almost always confirmed.  Nonetheless, there is indeed a shortcoming in the education of most of our students that I’ve seen year after year- and this certainly carries into the Residency years.  Specifically, I am referring to the lack of education in basic biostatistics, research design, and critical analysis of the medical literature.

Statistics - the Unloved Stepchild of Science

If you are like me, you avoided statistic classes like the plague. I never took any such courses in college and none were even to be offered in Podiatry School.  Of course, in those days, I couldn’t begin to comprehend what a deficit this would leave in my education. (I also admit that if I had the option not to take such courses, I would not have).  I doubt if my instructors at CCPM even knew basic biostatistics, never mind epidemiology and study design beyond case series.  This weakness in my professional training became quite evident when I researched an extensive number of articles in preparation for writing and editing my first textbook over 20 years ago.  At that time, I came to the stark realization that I didn’t have a clue about statistics.  I had no idea what a p-value really was or meant, never mind the difference between a t-test and a Chi-squared test.  If you mentioned multiple or logistic regression to me, the glaze would start coming over my eyes.  And yet, in every research paper read, there were statistical analyses comparing different treatments and outcomes. Reading the numbers really didn’t make much of an impact, because I didn’t know what they meant. An Odds Ratio (OR) was indeed odd to me because I didn’t even know what odds were (I’m not a gambler). Of course, descriptive statistics were great because frequencies such as percent, means, and medians were easy to comprehend and made clinical sense. But standard deviations, standard errors of the mean, confidence intervals, distributions, alpha, beta, and 1-beta (power) were mysterious statistical concepts that I thought I could get away without knowing.  But I was wrong.

Statistics are the Language Used in Medical Research

How can one read current medical literature without having a basic working knowledge of biostatistics?  Almost every paper we read (even in Podiatric Journals) now includes statistical methods to ascertain significance of the differences between means or medians, or associations between risk factors and outcomes of interest (odds ratios, risk ratios, hazard ratios, etc.).  Can you honestly say that you know what a p-value is? What does the “p” stand for? How about that mysterious ninety-five percent confidence interval (95% CI)? Can you identify a statistically significant difference between means just by looking at the confidence interval? How about a significant Odds Ratio or Hazard Ratio? Do you know the difference between an adjusted and non-adjusted Odds Ratio? Why does it even matter? If the answer to these questions is no, how does one interpret the significance of a reported result? How do you critique a paper and assess its relevance to your practice?

These were my dilemmas years ago and I felt very unprepared to make a move into academic medicine.  It soon became evident that understanding statistical analysis is needed to stay abreast of developments in medicine and surgery as a private practitioner – to be an educated consumer of medical literature. That is when I took a big gulp and decided to get a graduate degree in Public Health with a concentration in quantitative methods. Mind you, I do not like math and have no special aptitude for it.  So when my counselor informed me that my needs would best be fulfilled through this concentration, I shuddered at the thought – and never looked back.

It is a harrowing process, and one that can be made better by educating and preparing yourself. I would offer...

The Power of Numbers

The power of numbers has subsequently amazed me - How numbers and equations can have so much meaning in Podiatry. It’s all about probabilities, proportions, and percentages – even these are all essentially the same thing.  By the way, that “p” in p-value refers to PROBABILITY. It really is all about numbers- the more numbers of people you have in your study, the narrower the distribution becomes, the narrower the standard deviation, and it becomes easier to detect differences between two populations (study groups) – given the fact that a difference really exists. This is called the "power" of a test and power is driven by – you guessed it – numbers.

Although not a statistician, in the following series of articles, I will try to explain- from a clinician’s stand point- the essentials that you should know if you are to be educated consumers of the medical literature. We’ll talk about p-values, distributions, 95% CI, and the like, as well as t-tests, Chi-squared tests, and logistic regression. Equally important, we’ll need to discuss study designs in preparation for that research required as a part of your residency. Nothing fancy, just basic stuff with a few references so that you can check my facts. It will be a Primer, not a statistics course, in preparation for your career.

My hope is that you too will be amazed at the Power of Numbers...

See you next time.

Robert Frykberg, DPM, MPH
PRESENT Editor,
Diabetic Limb Salvage

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