In the summer of 2005 one of us was presenting at a conference arranged by one of the leading US consulting houses for senior executives. Like so many other conferences that litter today’s global executive network, the topic of the conference was ‘Making HR Transformation Work’. A partner of the consulting house had heard one of us speak at another conference and was intrigued by our alternative view that we should aim to understand how human resource management (HRM) achieves its impact, not through measurement and prediction, but through explanation, and using a philosophical approach called critical realism.

As is the wont at such conferences, a cartoonist had been hired at great expense to the hosts. The cartoonist was charged with the responsibility of capturing the essence of what was being said, which would appear on a huge screen behind the presenter. As one of us began to articulate our critique of the way in which businesses currently seek to ‘measure’ how HR unlocks the performance of people, the cartoonist first drew a picture of a giant canary blocking access to the shaft of a coalmine. In an instant, the cartoonist had captured what we were trying to say. In order to establish if a mine was filled with poisonous gas, miners would often release a canary into the mine. The hypothesis deployed was a simple one: were the canary to stop singing, it was deduced the mine was probably unsafe.