TY - JOUR
T1 - Validation of the food access survey tool to assess household food insecurity in rural Bangladesh Biostatistics and methods
AU - Na, Muzi
AU - Gross, Alden L.
AU - West, Keith P.
N1 - Funding Information:
The study was supported by Bill and Melinda Gates Foundation (Grant OPP 614) and Sight and Life Global Nutrition Research Institute Fellowship. We gratefully acknowledge the analytic guidance of Karen Bandeen-Roche and contributions to the study by Parul Christian, Alain B Labrique, Rolf Klemm, Saijuddin Shaikh, Hasmot Ali, Abu Ahmed Shamim, Rezwanul Haque, Sucheta Mehra, Lee Shu-Fune Wu and Maithilee Mitra. We thank Amanda Palmer, Sameera Talegawkar and Bess Lewis for their valuable comments on the manuscript.
Publisher Copyright:
© 2015 Na et al.
PY - 2015/9/7
Y1 - 2015/9/7
N2 - Background: Perception-based Likert scale are commonly used to assess household food insecurity. The aim of this study was to evaluate the psychometric properties and external construct validity of the 9-item Food Access Survey Tool (FAST) in a population-based randomized controlled trial. Methods: Participating women (n∈=∈11,992) were asked to recall the frequencies of nine food insecurity experiences over the past 6 months on a 5-point Likert scale. The Rasch partial credit model was used to study the item category severity and differential item functioning (DIF) by literacy status, respondents' age, land ownership and household sizes. Principal component analysis (PCA), non-parametric methods, and cumulative ordinal logistic regression models were applied to examine the Rasch model assumptions, namely unidimensionality, monotonicity and measurement invariance (non-DIF). Results: All items demonstrated good model fit with acceptable values of fit statistics (infit). PCA as well as other indices (Cronbach's alpha∈=∈0.85, scalability coefficient∈=∈0.48) indicated that all items fit in a single statistical dimension. The ordered responses of nine items displayed monotonic increasing item category severity as expected theoretically. All nine items were flagged with statistically significant DIF between key demographic - and socioeconomic subgroups (p∈<∈0.001); however, none of the detected DIF was considered practically significant given small effect sizes (variance explained by group membership and interaction term∈<∈1 %). The total summed score over the polytomous FAST was inversely associated with household wealth, dietary diversity score and maternal body mass index, demonstrating external construct validity. Conclusion: The polytomous FAST is internally and externally valid tool to measure household food insecurity in rural Bangladesh. Validation of this type of studies are recommended for similar Likert food insecurity scales.
AB - Background: Perception-based Likert scale are commonly used to assess household food insecurity. The aim of this study was to evaluate the psychometric properties and external construct validity of the 9-item Food Access Survey Tool (FAST) in a population-based randomized controlled trial. Methods: Participating women (n∈=∈11,992) were asked to recall the frequencies of nine food insecurity experiences over the past 6 months on a 5-point Likert scale. The Rasch partial credit model was used to study the item category severity and differential item functioning (DIF) by literacy status, respondents' age, land ownership and household sizes. Principal component analysis (PCA), non-parametric methods, and cumulative ordinal logistic regression models were applied to examine the Rasch model assumptions, namely unidimensionality, monotonicity and measurement invariance (non-DIF). Results: All items demonstrated good model fit with acceptable values of fit statistics (infit). PCA as well as other indices (Cronbach's alpha∈=∈0.85, scalability coefficient∈=∈0.48) indicated that all items fit in a single statistical dimension. The ordered responses of nine items displayed monotonic increasing item category severity as expected theoretically. All nine items were flagged with statistically significant DIF between key demographic - and socioeconomic subgroups (p∈<∈0.001); however, none of the detected DIF was considered practically significant given small effect sizes (variance explained by group membership and interaction term∈<∈1 %). The total summed score over the polytomous FAST was inversely associated with household wealth, dietary diversity score and maternal body mass index, demonstrating external construct validity. Conclusion: The polytomous FAST is internally and externally valid tool to measure household food insecurity in rural Bangladesh. Validation of this type of studies are recommended for similar Likert food insecurity scales.
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U2 - 10.1186/s12889-015-2208-1
DO - 10.1186/s12889-015-2208-1
M3 - Article
C2 - 26346311
AN - SCOPUS:84941140917
SN - 1471-2458
VL - 15
JO - BMC public health
JF - BMC public health
IS - 1
M1 - 863
ER -