In reply: We thank Middleton et al for their interest in our article. As 96% of questionnaires in our ASAP study1 were completed by September 2000, their study (as yet unpublished) and ours were not concurrent. Statistically, based on the information given by Middleton et al, we would expect 5.5 GPs (296 x 333/18066) to be involved in both studies. Chance, or because direct involvement in the ASAP study had finished months earlier, may explain why none of the doctors in the survey by Middleton et al stated that they were involved in a stroke audit.

In answer to the claim that "no GP data by State and Territory" were provided, we did in fact indicate in our article how many GPs from each State and Territory participated.

Intracluster correlations (ICCs)2 for each risk factor in our study are shown in the Box. ICCs have a greater effect on sample size than on CIs, because CI width is inversely proportional to the square root of the sample size. The large sample size of ASAP means that the study has acceptable precision, even after allowing for ICCs.

Overall estimates for risk factors were provided for the population of people consulting GPs, which is the relevant population. We would not necessarily expect the same distribution of risk factors in people not attending GPs. Age- and sex-specific risk-factor prevalences, shown in Box 3 of our article,1 can be used to calculate age- and sex-standardised rates for any desired population.

We are confident that the information obtained in our study is likely to be representative of most Australian general practice environments.