Meaning. We all look for it in our lives. Why are we here? What are we doing? Why do we make the choices we do? Why did my fortune cookie say beware of baked goods? If you are hoping that I answer these questions – I apologize in advance. The meaning I want to discuss is that which we assign to numbers and that they subsequently convey to us…or at least appear to.

Numbers are an inseparable part of our lives. In their purest form, they make sense. Zero (0) represents an absence, one is more than zero, and four is two times more than two. In their simplest form, numbers are pure and straight forward. However, we leverage numbers to define and describe and, thus, inadvertently make the pure murky. There are sinister instances where the pure is purposefully made murky – those jerks.

Everyday, whether you notice it or not, numbers are presented to us as a way to convey meaning, provide value, aid in understanding, and persuade. From the simple “3 out of 4 dentists recommend Nothing but the Tooth toothpaste,” to average ER weight time, to metrics such as GDP, we see these numbers and sometimes say, “that makes sense” without much thought and move on. But here’s the catch – a number is just a number. Apologies for the anthropomorphism (fancy way of saying I’m assigning human characteristics or behavior to something not human) – but a number is blind to the context. It doesn’t presume to know or care about how we use it. We assign the context and, subsequently, the manner in which that number is calculated and given meaning. It is this characteristic that should always lead us to ask the most basic questions when presented with a number, statistic, or metric – questions as basic as “is that a big/small number” or “how do you define/calculate X.” These seem elementary and may likely evoke anxiety right before you ask them – but I bet you encounter a few And then it hit me… moments when you do. Let’s talk about a few examples.

Increase Risk of Cancer

Cancer, in its numerous forms, is scary and concerning. Most of us know of someone who has been afflicted by cancer. Even worse, we likely know someone whose life was tragically cut short because of cancer. Although modern medical advances have made huge strides in detection and remediation of cancer diagnoses, the term itself is still a cause for alarm for most. This concern can be seen in the amount of resources spent on further understanding cancer and cancer treatments. It can also be seen in the number of studies and popular press reports that share new cancer discoveries. However – the myriad of reports that highlight incident rates and cancer linkages can create a kind of “everything causes cancer” perception. These reports demonstrate eating this, drinking that, engaging in this activity increases your likelihood of cancer.

Now, to be 100% clear – cancer is a scary, dangerous, and sometimes deadly disease to be taken seriously. I do not mean to lessen this impact at all – the outcome of cancer likelihood analyses is completely different than the outcome of precipitation likelihood analyses: cancer vs. the need for an umbrella. However, a sense of learned helplessness (“everything causes cancer”) and an unnecessary level of concern from minute increases in incident rates is not necessarily helpful either – so let’s talk about those likelihoods!

About 16 years ago, BBC News Online published an article stating that research had shown that the risk of breast cancer increases 6% for every alcoholic drink consumed.¹ There are two things to point out here – 1) their interpretation of the actual findings was just wrong and 2) this is key here – knowing the increase in risk is meaningless without knowing the baseline risk. Let’s just get the first point out of the way.

The original study actually claimed that a women’s risk for breast cancer increases 6% for every alcoholic drink per day on average. The difference may not seem obvious, but it is incredibly important. Six percent for each alcoholic drink consumed means that the majority of women would likely have breast cancer after their 42nd alcoholic drink, ever. It appears this error has since been corrected as the reference to this reporting is second hand and the current article has clarified the finding.² Six percent for every alcoholic drink per day on average means that if you, on average, drink one alcoholic drink per day – your likelihood of breast cancer has increased by 6 percent. If you have two drinks on average, that’s 12 percent.

The second (and most important point here and when you EVER hear a percentage being used) – what is the baseline? Why does the baseline matter? Imagine a scenario where a company with 1,000 employees, in an attempt to improve their image of valuing diversity, states that they have increased the number of minorities by 300%! It sounds impressive – but how many minorities were there to start? What if initially there was one and now there are four – is that as impressive? Of course there is a lot of contextual information that might go into fully evaluating that question, but suffice it to say that “we’ve hired three more minorities” sounds less impressive than “we have increased the hiring of minorities by 300%.”

Now that we have that out of the way – let’s return to the baseline of breast cancer. In 2008, the world-age-standardized incidence rate of breast is 89.9 per 100,000. Let’s make it even easier – for every 100 women, 8.9 are expected to develop breast cancer. Now, back to our increase rate of 6%. Increasing our baseline rate of 8.9 by 6% (8.9 * .06) gives us 9.4 out of 100 women. What does that mean? About 9 out of 100 women will get breast cancer – if all women were to drink, on average, one alcoholic beverage per day, that proportion would increase to 9.4.

Again, context matters here an I’m not advocating for ignoring medical advice, recklessly consuming alcohol, or abandoning the healthy choices you have made for yourself personally. Instead, I’m hoping that when you hear a number you take time to understand what it means. In the end – that’s what counts!

Check back for Part 2 where we discuss ER Wait Times and some sneaky Airline metrics.

1. https://consumer.healthday.com/health-technology-information-18/press-medical-and-health-reporting-news-552/health-highlights-nov-nbsp-13-nbsp-2002-510245.html

2. http://news.bbc.co.uk/2/hi/health/2445273.stm