01 January 2010

Wrong Correctness | Bruce Eckel

Wrong Correctness | Bruce Eckel

Some interesting points:

Estimation

DeMarco and Lister first point out something very important. When someone asks you how long a particular subproject will take, it's usually implicit, and sometimes explicit, that they want to know the shortest, most optimistic time for this task. DeMarco and Lister note that the actual time for finishing a task is a probability curve, and if you only ever give the shortest time, you are giving the leading edge of the curve, where it touches the axis. Thus, each subtask prediction has a 0% probability of being correct. This means your project completion time estimation starts out, from day one, with a 0% probability of being correct. They suggest a relatively simple change in behavior: give, instead, the middle of your probability curve for each subtask, so you begin with a palpable completion time. It doesn't make the completion time predictable, but it does make it significantly less wrong.

People not resources

Steve Blank tells a story that's been repeated in many forms: the seemingly small, one-logical-step-at-a-time event that makes the key players look up and notice that the company has just gone from sweet to sour. In this case it is the slightly-comical decision by a new CFO to stop providing the human resources with free soda, which was costing the company some 10K/year. An easy and rational call, which made the CFO look like a go-getter. The key engineers, once sought avidly by the company, quietly announced their availability and began disappearing. The company didn't panic because it had already gone through its change of life and become more important than its pieces; it was no longer an idealistic youth who valued things like people and quality of life. It had grown up and matured and was now in the adult business of making money. Workers had become fungible resources, easily replaceable.  I remember the first time I saw this happen, in the second company where I had a "real job" after college. I'm not sure what the inciting incident was, perhaps the 3rd or 4th business reorganization within a couple of years, perhaps a sudden withdrawals of bonuses and raises. Whatever the case, a number of the engineers that I considered to be extra-smart began quietly disappearing, with the company making no-big-deal noises as this happened. My own direct manager left, which should have been cold water in my face (but I typically have to learn things in the hardest possible way, and this lesson was -- eventually -- not lost on me).  When did we decide that we were no longer "personnel" (which at least sounds personal) but instead the resources that are human?

Problem with standard interviews for selecting people

Gladwell tells the story of outstanding college football quarterbacks, the majority of whom are abject failures in professional football -- because the game is played entirely differently in the two domains. Thus, you cannot predict the success of a quarterback based on their success in college. Later in the book, he looks at the way we interview prospects for jobs. It turns out the most critical point of the interview is the initial handshake (or other initial impression). If you like the way someone shakes hands, you take whatever answers they give you and adapt them to that first impression. It's basically a romantic process, except with a real romance you decide the outcome after many months, whereas with a job interview you decide after only hours -- or actually in a moment, with the initial handshake. Even our lame attempts to simulate "real" work (by asking programming puzzles, for example), tell us nothing about the truly critical things, like how someone responds to project pressure. We suffer from Fundamental Attribution Error -- we "fixate on supposedly stable character traits and overlook the influence of context," and we combine this with mostly-unconscious, mostly-inappropriate snap judgments to produce astoundingly bad results. Basically, we think that someone who interviews well (one context) will work well on a task or in a team (a completely orthogonal context).  The answer is something called structured interviewing, which changes the questions from what HR is used to -- questions where the answer is obvious, where the interviewee can generate the desired result (not unlike what we've been trained to do in school) -- to those that extract the true nature of the person. For example, when asked "What is your greatest weakness?" you are supposed to tell a story where something that is ostensibly a weakness is actually a strength. Structured interviewing, in contrast, posits a situation and asks how you would respond. There's no obvious right or wrong answer, but your answer tells something important about you, because it tells how you behave in context. Here's an example: "What if your manager begins criticizing you during a meeting? How do you respond?" If you go talk to the manager, you're more confrontational, but if you put up with it, you're more stoic. Neither answer is right, but the question reveals far more than the typical interview questions that have "correct" answers.

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