Main Page/Research/Papers/fast food and arterials/AJPH/comments

reviewer	comment	PMH response
1	"you imply that once road density is considered SES no longer matters, but you do not consider that SES is also highly related to road density, both poverty and Fast Food are attracted to high density road/highway locations."
1	"Your findings also do not conflict with previous work that suggests that access to fast food is a factor in obesity prevalence; in fact your study supports this hypothesis."
1	"Page 6 describe how distance from residence to fast food is determined – crow fly or network distance"	will clarify that this is Euclidean distance
1	"Level of poverty (7-8%) with such a low portion of the sample in this category would it be better to use median household income rather than % below poverty in your models? (see page 9)"
1	"Page 8 Table 3 and the text do not match, the last line on page 8 says ‘percent non white was again not significantly associated, but in the table % non white for all tracts was listed at p=.046. Also, should pop density be included in the table, it is described in the text as if it were also in the table?
1	"Discussion I do not follow your argument in the last paragraph (page 11) ‘Physical access to fast food measured by proximity or density may not be the most important determinant of fast food use’ I agree it is not the most important factor, but your study indirectly supports the hypothesis that access IS an important factor. Your study supports the hypothesis that amount of traffic passing by a location is an important factor in determining location of fast food outlet. It also supports that idea that more affluent people live in less dense locations further away from fast food (and nearer white table cloth restaurants?)"
1	"Table 4 Should you explain the implications of your findings that %non white is significant in both models and in the opposite direction than what was expected and found in the Pearson correlations (table 3)"
2	"By the way, what kind of correlation is there between freeway/arterial density and SES?"
2	"The authors should think about the difference between analysis that aims to explain why a situation exists and analysis that aims to describe a situation that might help to explain outcomes of interest. By incorporating freeway/arterial density, they seem to be aiming for the former. But this is a less important question. If there are greater concentrations of fast food outlets in low SES areas, we need to understand the implications of this situation and find ways to respond to it, regardless of the cause."
2	"The one concern I have methodologically is in the use of census tracts for measuring fast food density. The question is whether the density within one’s own census tract is a good measure of one’s access to fast food, when density can vary considerably from tract to tract. If the fast food outlets near me, for example, happen to be on the other side of the arterial street used as a boundary for my census tract, I might have 0 density, while the tract right next door has a high density. An alternative is to use an average density for the tract and its adjacent tracts, weighted or unweighted. This approach presents its own challenges, and doesn’t guarantee a more accurate result, but the authors need to discuss the possibility that the definition of areas (census tracts, in this case) can influence the results. This is an example of the modifiable area unit problem (MAUP), on which there is a rather substantial literature."
2	"I was also curious about the measure of distance from each dwelling to the nearest fast food restaurant. This is a much better measure of accessibility than average density for a tract. Yet the authors seem to use this solely for descriptive purposes. Is there some way to use this measure as a dependent variable? What if you use the average distance for all residences within a tract, rather than tract density? This would largely eliminate the problem with the census tract density measure noted above."