## Tuesday, July 21, 2015

### What Are the Odds?

Are you ready for some creative math?

When I first visited my fertility clinic last spring, the nurse practitioner I met with told me I had a 5% chance of a successful outcome (e.g. taking home a baby) at my age - which was then 40.  She actually took back the paper she had given me earlier, with all of the general information about IUI (intrauterine insemination), and dramatically crossed out the printed 20% and scrawled "5%" above it.  She didn't want me to get the idea that I might be as fertile as someone who had the good sense to come in at age 27 or 33.  A few weeks later, after all of my lab results showed no menopause in sight, she increased the probability to 8%.

Now there are a couple ways you can look at this.  You can think, even if I put some top-notch sperm right up close to my egg at the most fertile moment possible, there's still a 92% chance that I won't be able to have a baby.  Here's what I say to that: unacceptable!

Let's try again...

Okay, even a normal, fertile, young couple supposedly only has a 20% of getting pregnant in any given month.  According to a lazy Google search, The Bump says that by the time you reach 30, the odds go down to 15%.  The vast majority of healthy children that I know were born to mothers in their 30s, without much effort.  I'm going to embrace this availability bias  and decide that 15% is not bad at all, in real-world terms.  Given that decision, I'm only half as likely to get pregnant as a 30-year-old, right?  53.33% as likely, in fact.  And even if you take my advanced-age eggs into account, which decreases the odds of viability by about half, that's still over 26%.  Which is a happier number than 8%, by far.  Are you still with me?  Who says math can't be fun?!  The point is, look at all the millions of people in the world having babies left and right, many of them unplanned.  And the odds were only 15%!

Sometimes I think data, facts, statistics, and even reality are overrated.  But if I do consider them, that also means I have to take into account all of the factors that haven't been calculated into that 8% by the medical professionals.  They never asked me about how healthy my diet is or how often I exercise or whether I'm taking vitamins or how much emotional support I have or whether I suffer from anxiety or depression or delusional optimism or anything else.  All of those are bound to have some affect on fertility, right?

When it comes right down to it, making predictions and assigning probability to a particular outcome based on what has happened in the past is a dodgy game at best.  As Philip Tetlock has shown, expert predictions on average tend to be only slightly better than random guessing.  Of course, the kinds of predictions his experts were making (about politics and world events) were different than medical predictions.  But if anything is as complex and mysterious as the modern political landscape, it might be the creation of a new human being.

How many times have you seen something happen that you never would have predicted?

Just this morning, I came upon a flock of ten chickens in a neighbor's yard.  I've been passing this yard every few days for the last ten years on my neighborhood walks and I have never seen anything other than a stray cat or a squirrel.  It is actually illegal to keep more than three chickens within city limits.  These chickens totally shouldn't be here!  Yesterday, nothing could have convinced me to assign a high probability of finding ten chickens in this spot.  And yet, there they were!

And this: I am the kind of driver who always uses her turn signal.  I could be driving along a country road at two in the morning with no other cars for miles and I would use my signal purely out of habit.  But the other day, I made a last-minute lane change and flicked my signal on only momentarily.  And wham, out of nowhere, a motorcycle cop zooms after me and hands me a \$136 ticket for not using my signal.  I'm not gonna argue with the guy, so I take the ticket politely, fuming internally.  But then I thought, "This just proves that crazy, unlikely events can happen out of nowhere even though there is no logical reason for them!"  If annoying unlikely events can happen, then miraculous and wonderful events can happen too.

You just never know.  The world is full of the unexplained, the unexpected, the never-thought-it-would-happen.  Impossible things are happening every day!  Today, whether its realistic or not, I'm choosing to believe I'll beat the odds.

Sending good luck charms and wildly optimistic predictions to all,
E