Battersby et al present a method of performing equity audit where data on incidence, deprivation, and surgical resection rates of non-small cell lung cancer are compared.¹ Deprivation was measured using the Index of Multiple Deprivation (IMD) 2000² and all analyses were performed at the primary care trust (PCT) level. Battersby et al report no statistically significant associations between their measure of deprivation and age and sex standardised incidence of non-small cell lung cancer. This is highly unusual and in contrast with findings from a large number of different populations.^3–9 Without clear evidence that there is something exceptional about the population studied by Battersby et al, the lack of association between deprivation and incidence of lung cancer is likely to be an artefact.

Two possible explanations of Battersby et al …