Not that multiverse

I recently started reading the book "Fooled by Randomness" by Nassim Taleb. So far it is not a book I would recommend to most people (the person who suggested I read it said he usually recommends people start with his most recent book, Antifragile). The author covers very interesting content, but not in a way that is easy to follow or digest. This is the first of probably (hopefully?) a series of posts trying to translate the subject of Taleb's book to an easier to digest format.

While I lived in Ann Arbor during graduate school there was a turn I had to drive about once a month. The unfortunate thing about this turn was that it was a left turn immediately after taking a left at a light. It was so close that I had to make a decision: either move into the middle lane of the road, which was a left turn lane for traffic coming the opposite direction, or remain in the line of traffic, and wait for any oncoming traffic to be clear.

After a few times of taking the turn, I wondered which of the two not-great options I should choose going forward. It seemed to me that I could either risk a low likelihood of a head-on-collision, or a relatively higher likelihood of being rear-ended in the other lane. I settled on staying in my lane and risking being rear-ended because of how much more destructive head-on collisions are.

A few years after making the decision, I made the left turn, and waited for the oncoming traffic to clear as usual. The person who was driving behind me saw the brake lights and stopped. Unfortunately, the person behind them didn't and bumped the middle car into mine. It was fairly minor damage all around, but it is easy to wonder given what happened if I actually made the right choice.

One of the messages from Taleb is that there is complexity in judging the quality of a decision based on random outcomes. For the person who bought a lottery ticket and won, it was a good decision. However, we should advise each person not to buy lottery tickets because in most versions of the universe, the individual you are talking to does not win. 

This notion of "most versions of the universe" is a useful one when talking about randomness since it lets you still give weight to things that didn't happen. And while it can be a good idea to update your estimates of probabilities as you get new information, the fundamentals before an event are the same as they are after. As an example, after being rear-ended I did conclude that maybe I should be a bit more aggressive in taking my turn between oncoming traffic. But the fundamentals of my decision didn't change because of it.

Soft vs. Hard constraints

​Last week, at a meeting to prepare for an on-site kickoff with a client, I was asked if I had any real-life examples of the "squishy rules"​ I wanted to discuss with the customer. At first nothing was coming to mind, but my airline helpfully solved that problem for me on my way to the kickoff.

After I had started my first flight, my second flight was cancelled. I found myself in the customer service line behind several other people also trying to figure out how to satisfy their constraints and priorities in the best way possible (scheduled meetings the next day, no private jets, how far were they willing to drive a rental car). What struck me was how much those constraints and priorities varied among the 4 people ahead of me in line. Some people were fine with getting in the next night, others (like me) were willing to give up anything except being on time the next day.

Now, you may have noticed above that I combined constraints and priorities into a single list. When I had booked my flight, I chose to fly to the actual city I was headed to. Once that flight was cancelled, I had a choice to make. What used to be two hard constraints now gave me zero "feasible solutions" -- I could either miss one day of the one-and-a-half day kickoff, or I needed to fly to a different city. Now, some very creative people find themselves in this situation and will fly to some other middle city and then to their destination. But my airline either didn't or couldn't suggest those options, and if you had asked me before the cancellation if I would consider a 3-leg trip, I would have given a flat no. So if I had no possible solutions, what could I do?

Well, this happens a lot. People will often list their preferences as needs until pressed. And as long as there is a feasible solution, it doesn't have to become obvious. One of the people ahead of me in line chose not to give up any of their hard constraints, which meant there were still no options available. It was obvious that something had to give unless the goal had changed -- nevermind, I didn't need to go to that city after all. But knowing which of your rules to turn "squishy" is the key to still achieving your goal.

In my case, I flew to a neighboring city instead. In fact, my boss had flown directly to my alternate city and planned from the start to drive the remaining distance -- he had never made flying to the final city a constraint. As a result of this experience I also finally bought some plane tickets for the summer I had been putting off for weeks. I am now flying to the 2-hour-away airport for less than half the price of the tickets to the actual city.

Have you ever realized you were overconstraining your problem? Which constraints turned out to be a lot squishier than you realized?

​You can't inspect in quality

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This is just a short post on applying industrial engineering principles to daily life.

At some point in my education, someone told me that it is impossible to inspect in quality. At the time it made sense from what I knew about inspections: people are bad at noticing rare events. 

Since then I have found a semi common application at home where attempting to inspect in quality is both tempting and a bad idea... Cleaning up broken glass. I have no idea how other people do it, but the system I have found to avoid the unpleasant outcome of stepping on glass is to clean extremely thoroughly twice, and then to conduct my first inspection. If I find any glass, I assume there are several more pieces I missed and do another cleaning pass.

Do you have any tips to speed up this process? Thoughts of other scenarios where it is tempting to try to "inspect in" quality? Leave your thoughts in the comments!