Most of my consultancy work boils down to devising ways in which clients can maximise the validity and quality of work by lay staff or volunteers whilst minimising the impact of inevitable errors. And my email inbox is rarely without a plaintive request (open or veiled) for informal guidance or reassurance on a conclusion in which the sender lacks the confidence necessary for exposing it to peer scrutiny.
In the real world, whether we statisticians like it or not, an overwhelming majority of statistically based decisions and statistically oriented actions are taken by nonstatisticians.
Having made such a sweeping statement, it would be prudent to take a moment for definition of terms. What, exactly, is a nonstatistician?
In my own practice, there is no single clear cut answer to that. The word is not the binary divisor which it pretends to be: just a shifting pointer on a continuum. That’s why I used the alternative description "lay staff" in my first paragraph, above: because it’s less complicated. All too often, individuals with the same level of expertise will place themselves very emphatically on opposite sides of the pointer. In one market segment with which I am very familiar, professionals who are hazy about the difference between mean and mode are counted as statisticians and make million euro decisions based on statistical grounds. In another, science graduates whose degree transcripts include passes in all the usual statistics courses claim to be completely baffled by the subject.
Reading through the literature of any professional area, but particularly in the medical and life sciences, one finds frequent reference to this. [more...]