How to deal with the shrinking half-life of knowledge

Knowledge has a half-life, and that half-life is getting shorter every year.

When John Browne was CEO at BP, he talked about "the shrinking half-life of ideas". This always struck me as a very interesting concept; one which was fundamental to Browne's approach to corporate KM. I have since found that he was quoting an older idea from 1962 concerning the shrinking half-life of Knowledge, which has now been popularised and explored by Sam Arbesman (see video) among others.

The idea of a half-life comes from nuclear physics, and originally applied to the decay of radioactive nuclei. This quote (now no longer online) from the people behind the popular QI program tells us

"What we think we know changes over time. Things once accepted as true are shown to be plain wrong. .... But what's really interesting is that studies of the frequency of citations of scientific papers show they become obsolete at a predictable rate.  

Just as with radioactive decay, you can’t tell when any one 'fact' will reach its expiry date, but you can predict how long it will take for half the facts in any discipline to do so. In medicine, for example, 'truth' seems to have a 45-year half-life. Some medical schools teach students that, within a few years, half of what they’ve been taught will be wrong – they just don’t know which half. In mathematics, the rate of decay is much slower: very few accepted mathematical proofs get disproved

Not all knowledge has a short half-life - sometimes the knowledge is linked to the technology, and if you are running a nuclear power station using 1960s control software, then the half-life of the knowledge of the software has to exceed the life of the power station. However in most other areas, where knowledge is evolving and changing, and your competitive advantage lies (at least partly) in having the best and most valid knowledge, then hanging on to old knowledge which is past it's half-life can be competitively dangerous. And the faster the speed of change, the shorter the half-life of knowledge and the greater the danger of using obsolete knowledge.

The implication for KM

Where knowledge has a short half-life, Knowledge Management is not so much about documenting and protecting "what you know", it is about how fast you can know something new, and how easily you can let go of the old. That's what will win you the battle with the competition. Colonel Ed Guthrie of the US Army used to liken this constant learning to the aerial dogfights in world war 1. "In those days" he used to say, "It was about getting inside the other guy's turning circle. That's what would win you the engagement. Now it's about getting inside the other guy's learning circle".

This implies that any knowledge which has been documented must constantly be re-examined in the light of new lessons and new experiences, and obsolete knowledge must be constantly updated or archived. New knowledge must be rapidly disseminated to replace old knowledge, just as updates to pilots checklists are rapidly disseminated. 

A knowledge base full of old documents runs the risk of containing old "facts" which are no longer true. This is why some organisations require subject matter experts to continually update practice collections, and why others use constantly-updated wikis to store knowledge, especially where knowledge is changing rapidly and has a relatively brief half-life. So beware if your strategy is to use search and AI to interrogated the documented knowledge in your organisation, as this often lags behind the evolving state of knowledge. 

Be aware of the shrinking half-life of knowledge, and be prepared for constant knowledge update if the half-life is short.