The trend towards shorter iterations, while being a good demonstrator of increasing development capability, also tends to rob planners of an opportunity to step back from project minutiae.
Experiments in cognitive science and social psychology have revealed a wide variety of biases in areas such as statistical reasoning, social attribution and memory. It’s argued these biases are common to all human beings, and some have been demonstrated to hold across very different cultures.
Cognitive biases were first identified by Amos Tversky and Daniel Kahneman. They claim biases are artifacts of problem-solving heuristics humans use. Recent work on cognition in other animal species reveals that some cognitive biases are not unique to humans, suggesting an evolutionary origin.
Whatever the mechanisms behind cognitive bias, we have good data to suggest that under some circumstances we all have a tendency to react in a way that seems surprising when viewed from a more detached perspective.
I’ve noticed a pattern in which people regularly over-commit to work and consequently regularly under-deliver, and don’t seem able to break the cycle. In fact, their actions seem to perpetuate the cycle.
When you estimate how long something will take, about half the time it should be done early or on time. Almost anyone reading this will know things are rarely done sooner than expected, especially if they’re difficult. People have been shown experimentally to be poor estimators, with a marked bias towards underestimation of time required to complete tasks.
The morning stand-up meeting is one of the well-known features of XP (though oddly not a “practice”). A few years ago I worked for Connextra, one of the XP pioneers in the UK, and over the years I’ve come to realize there was an important difference about our stand-ups - something I haven’t seen anywhere else.