The study has several other limitations the focus of

The study has several other limitations. The focus of this research was on the price differentials in
different store types, but the effect of those differentials on food purchase decisions must be explored
in future work. The study also did not include WIC stores, which may be source of competition for
smaller stores in this study sample. However, inclusion of WIC stores in pricing studies presents
unique challenges, as WIC products are capped at 115% of the state average cost, and vendors may set
prices differently when customer are likely to pay with WIC vouchers. Finally, USDA food deserts
do not align perfectly with other measures of healthy food access. Food desert status can be defined
by many criteria, which may yield different boundaries [ 53 , 54 ]. Thus, results could vary if alternate
criteria were used to define low-income/low-access areas.
5. Conclusions
Taken in context with other studies, our results support the notion that, for staple food items
commonly stocked in smaller food stores, prices are generally higher in smaller stores compared with
supermarkets. More research utilizing a health equity perspective is needed to examine grocery prices
in different retail spaces, especially in food deserts where high food prices could contribute to food
insecurity. This research may be particularly relevant to the discourse on the upcoming Farm Bill
reauthorization in 2018, which addresses SNAP retailer authorization requirements. Such work can
also assist in identifying unanticipated consequences of the Minneapolis Staple Foods Ordinance
or other local policies related to minimum stocking of healthy food. Future research should
also examine the effect of pricing differentials on objective measures of shopping behaviors in
quasi-experimental studies.
Supplementary Materials: The following are available online at .
Acknowledgments: Research reported in this publication was supported by the National Institute of Diabetes
and Digestive and Kidney Diseases of the National Institutes of Health under Award Number R01DK104348 (PI:
M. Laska), as well as the Centers for Disease Control and Prevention under Award Number U48DP005022. This
funding supported the work of all authors of this paper. The content is solely the responsibility of the authors
and does not necessarily represent the official views of the National Institutes of Health, the Centers for Disease
Control and Prevention, nor the Department of Health and Human Services.
Author Contributions: Caitlin E. Caspi formulated research questions and lead manuscript writing;
Jennifer E. Pelletier led data analysis, contributed to writing/revision of the manuscript, and supported carrying
out the study from which these data originated; Lisa J. Harnack assisted in interpreting results and made
contributions to writing and revising the manuscript; Darin J. Erickson guided and provided feedback on
the analysis, assisted in interpreting results, and gave feedback on analyses and writing/revision of the