Robert Thomas has made an interesting comment on my blog, where he mentions "the fallacy of incrementalism". Robert says
"It's the fallacy of incrementalism - thinking you might do maybe 10% better next time. Yet at that rate it would take a huge number of repetitions to get from (our - when I did Bird Island) first 75cm tower to (our) second 3m+ tower. That's the difference between the top learners and the rest: it will take the incrementalists all eternity to catch up with the best learning organisations. A shift from an incrementalist standpoint is quite a fundamental shift"
The "top learner" takes learning from everywhere any anywhere - from other teams, and from records from the past. They challenge their thinking, they throw away their design if its unsatisfactory, they have open minds and welcome challenge. That's where we see the giant leaps in performance in Bird Island - with performance increases of 300% or 400%
The fallacy of incrementalism is that this is an effective way to learn. It's slow and steady, sure, but can be overtaken easily by the top learners.
The incrementalist approach represents learning only from your own performance. And we see in the Bird Island exercise that learning from your own performance gives estimated improvements in the order of 10% to 30%. They take their own design, and tweak it and stretch it. A team that learns incrementally, learns slowly.