The Fallacy of Using Administrative Data in Assessing the Effectiveness of Food Fortification. Comment on: "Folic Acid Fortification and Neural Tube Defect Risk: Analysis of the Food Fortification Initiative Dataset. 2020, , 247".

Our objective in this comment is to highlight several limitations in an ecological research study that was published in by Murphy and Westmark (2020) in January 2020. The study used data from the Food Fortification Initiative (FFI) website, and applying an ecological study design, made an error of "ecologic fallacy" in concluding that "national fortification with folic acid is not associated with a significant decrease in the prevalence of neural tube defects (NTDs) at the population level". We list study limitations that led to their erroneous conclusions, stemming from incorrect considerations regarding NTD prevalence, the average grain availability for a country, the fortification coverage in a country, the population reach of fortified foods within a country, and the absence of the consideration of fortification type (voluntary vs. mandatory), country-specific policies on elective terminations for NTD-affected pregnancies, stillbirth proportions among those with NTDs, and fortification implementation. FFI data are derived from many sources and intended for fortification advocacy, not for hypothesis testing. The flawed study by Murphy & Westmark (2020) in promotes a confusing and incorrect message to stakeholders, misguides policy makers, and hinders progress in global NTD prevention through a cost-effective, safe, and effective intervention: the mandatory large-scale folic acid fortification of staple foods.