His 1971 Rock Carling Fellowship monograph "Effectiveness and Efficiency: Random Reflections on Health Services", first published in 1972 by the Nuffield Provincial Hospitals Trust – now known as the Nuffield Trust, was very influential. To quote from the book's summary : "An investigation into the workings of the clinical sector of the NHS strongly suggests that the simplest explanation of the findings is that this sector is subject to severe inflation with the output rising much less than would be expected from the input". According to a review in the British Medical Journal, "the hero of the book is the randomized control trial, and the villains are the clinicians in the "care" part of the National Health Service (NHS) who either fail to carry out such trials or succeed in ignoring the results if they do not fit in with their own preconceived ideas". Maintaining this challenge to the medical care system as he saw it, in 1978, with colleagues, he published a study of 18 developed countries in which he made the following observations: "the indices of health care are not negatively associated with mortality, and there is a marked positive association between the prevalence of doctors and mortality in the younger age groups. No explanation of this doctor anomaly has so far been found. Gross national product per head is the principal variable which shows a consistently strong negative association with mortality." This work was selected for inclusion in a compendium of influential papers, from historically important epidemiologists, published by the Pan American Health Organization (PAHO/WHO) in 1988.