Examples of Research
Prenatal Feeding Intentions and Parity Predict Take-Up of the Supplemental Food and Nutrition Program for Women, Infants and Children
Social Science and Medicine, October 2013
It is impossible in most countries to randomize assignment into child health programs that may offer benefits. In the absence of this gold standard of program evaluation, researchers face the threat of selection bias—the possibility that there are unmeasured differences, relevant to outcomes, between those who are treated and those to whom they are compared. A common concern is that people who are eligible for a program but choose not to enroll may differ from those who do enroll. Because policies geared towards a country's most vulnerable people are determinants of health inequities, it is imperative that sources of selection bias be identified and that evaluation methods minimize the impact of selection bias on our estimations of treatment effects. Using a case study of a large Federal nutrition program in the United States, this study reviews how researchers have attempted to minimize selection bias and presents an analysis illustrating how the decision to take up the program can highlight sources of this bias. Relying on data from a longitudinal study of mothers and infants, I show that prenatal attitudes and beliefs may determine postnatal program enrollment, and that the direction of the bias differs by demographic variables. Further, I show that magnitude of supposed program effects vary significantly as a function of these prenatal beliefs. In sum, this paper makes the case for more careful study of the factors that determine take-up of a program, and inclusion of those factors in an evaluation of the program.
[Click Here for Paper]
Time of Birth, Breast Milk Feeding and Health Outcomes in the Neonatal Intensive Care Unit
Presented for Association of Public Policy Analysis and Management 2012 Meeting
Breast milk feeding in the Neonatal Intensive Care Unit (NICU) is associated with a host of improved health outcomes. However, breast milk feeding rates differ by socioeconomic status, race, ethnicity and maternal education indicating that these results are vulnerable to selection bias. Qualitative work by this author and others suggests that women giving birth in the late-night hours are less likely to begin a successful milk expression regimen due to the lack of experienced clinicians working during these shifts. Using the hour of birth as an instrument for breast milk feeding, this study attempts to isolate the effects of breast milk feeding on incidence of deadly conditions in the NICU, as well as the infant’s growth patterns and length of stay. This study also uses innovative measures of the indications for delivery type in order to construct a sub-sample whose distribution of delivery times is the most random, thereby increasing the validity of the analysis. The first-stage of the analysis revealed no significant relationship between late-night births and breast milk feeding at discharge, contrary to the claims of clinicians and mothers interviewed in a separate study. C-Section delivery and shorter maternal lengths of stay significantly predictive of decreased breast milk feeding at discharge, even after controlling for potential confounders. The reduced-form analysis suggests that infants born in the evening (5pm-Midnight) are roughly 2-4% more likely to contract Necrotizing Enterocolitis at some point during their stay in the NICU. The majority of associations between hour of birth and other health outcomes were insignificant. Evidence of heterogeneity in hour of birth effect size by birth weight, gestational age, race/ethnicity and maternal age were also explored.
[Click Here for Paper]
Clinician Perspectives on Barriers to and Opportunities for Skin-to-Skin Contact for Premature Infants in Neonatal Intensive Care Units
Breastfeeding Medicine, 2012. Volume 7 Number 2
Our objective was to investigate key factors in promoting skin-to-skin contact (STSC) in the neonatal intensive care unit (NICU). As part of a California Perinatal Quality Care Collaborative on improving nutrition and promoting breastmilk feeding of premature infants, a multidisciplinary group of representatives from 11 hospitals discussed the progress and barriers in pursuing the project. A key component of the collaborative project was promotion of STSC. Sessions were audio-recorded, transcribed, and assessed using qualitative research methods with the aid of Atlas Ti software (ATLAS.ti Scientific Software Development GmbH, Berlin, Germany). Two primary investigators studied the transcripts for themes related to STSC. Using an iterative approach, selected themes were explored, and representative quotes were selected. Barriers to promoting STSC fell into broad themes of implementation, institutional, and familial factors.The main challenge identified in implementation was defining a clinically stable eligible population of patients. Key institutional factors were education and motivation of staff. Familial factors involved facilitation and sustained motivation of mothers. In response to these barriers, opportunities for promoting STSC were enacted or suggested by the group, including defining clinical stability for eligibility, facilitating documentation, strategies to increase parent and staff education and motivation, and encouraging maternal visitation and comfort. Our findings may be useful for institutions seeking to develop policies and strategies to increase STSC and breastmilk feeding in their NICUs.
[Click Here for Paper]
Intent vs. Implementation--Food Allocation to Adult Males in WIC Households
Revise and Resubmit at the Journal for Nutrition and Health
The intent of the Special Supplemental Food and Nutrition Program for Women, Infants and Children (WIC) program is found in its name—to increase the health status of a targeted group through supplemental food. Households often contain multiple members who are categorically ineligible, including older ineligible children and adult males. This paper focuses on potential spillover of benefits to adult males. Comparing multiple outcomes across treated and untreated households, I find evidence that consumption of certain WIC foods is higher among men in WIC households compared to the most appropriate comparison group: income eligible non-WIC participants. I also find evidence that this difference is attributable to food-sharing and not an income effect as there is no increase in the consumption of other, non-WIC foods. The increased consumption of cereal, milk and juice is only remarkable among married men in WIC households and not among single fathers. Corollary evidence looking at the differences between married and single women’s food consumption suggests that food is siphoned from the mother and not from the children; this finding supports the altruistic parent food allocation hypothesis. Multiple outcome measures beyond food consumption are analyzed; men in WIC households consume less protein and calories. Most of the results are not robust to full controls, indicating that unobservable propensity to consume WIC foods may be driving entry into the program. If the findings of this study are a true representation of WIC implementation, policy makers should weigh whether this outcome is desirable in terms of the program mission.
[Click here for Paper]
Social Science and Medicine, October 2013
It is impossible in most countries to randomize assignment into child health programs that may offer benefits. In the absence of this gold standard of program evaluation, researchers face the threat of selection bias—the possibility that there are unmeasured differences, relevant to outcomes, between those who are treated and those to whom they are compared. A common concern is that people who are eligible for a program but choose not to enroll may differ from those who do enroll. Because policies geared towards a country's most vulnerable people are determinants of health inequities, it is imperative that sources of selection bias be identified and that evaluation methods minimize the impact of selection bias on our estimations of treatment effects. Using a case study of a large Federal nutrition program in the United States, this study reviews how researchers have attempted to minimize selection bias and presents an analysis illustrating how the decision to take up the program can highlight sources of this bias. Relying on data from a longitudinal study of mothers and infants, I show that prenatal attitudes and beliefs may determine postnatal program enrollment, and that the direction of the bias differs by demographic variables. Further, I show that magnitude of supposed program effects vary significantly as a function of these prenatal beliefs. In sum, this paper makes the case for more careful study of the factors that determine take-up of a program, and inclusion of those factors in an evaluation of the program.
[Click Here for Paper]
Time of Birth, Breast Milk Feeding and Health Outcomes in the Neonatal Intensive Care Unit
Presented for Association of Public Policy Analysis and Management 2012 Meeting
Breast milk feeding in the Neonatal Intensive Care Unit (NICU) is associated with a host of improved health outcomes. However, breast milk feeding rates differ by socioeconomic status, race, ethnicity and maternal education indicating that these results are vulnerable to selection bias. Qualitative work by this author and others suggests that women giving birth in the late-night hours are less likely to begin a successful milk expression regimen due to the lack of experienced clinicians working during these shifts. Using the hour of birth as an instrument for breast milk feeding, this study attempts to isolate the effects of breast milk feeding on incidence of deadly conditions in the NICU, as well as the infant’s growth patterns and length of stay. This study also uses innovative measures of the indications for delivery type in order to construct a sub-sample whose distribution of delivery times is the most random, thereby increasing the validity of the analysis. The first-stage of the analysis revealed no significant relationship between late-night births and breast milk feeding at discharge, contrary to the claims of clinicians and mothers interviewed in a separate study. C-Section delivery and shorter maternal lengths of stay significantly predictive of decreased breast milk feeding at discharge, even after controlling for potential confounders. The reduced-form analysis suggests that infants born in the evening (5pm-Midnight) are roughly 2-4% more likely to contract Necrotizing Enterocolitis at some point during their stay in the NICU. The majority of associations between hour of birth and other health outcomes were insignificant. Evidence of heterogeneity in hour of birth effect size by birth weight, gestational age, race/ethnicity and maternal age were also explored.
[Click Here for Paper]
Clinician Perspectives on Barriers to and Opportunities for Skin-to-Skin Contact for Premature Infants in Neonatal Intensive Care Units
Breastfeeding Medicine, 2012. Volume 7 Number 2
Our objective was to investigate key factors in promoting skin-to-skin contact (STSC) in the neonatal intensive care unit (NICU). As part of a California Perinatal Quality Care Collaborative on improving nutrition and promoting breastmilk feeding of premature infants, a multidisciplinary group of representatives from 11 hospitals discussed the progress and barriers in pursuing the project. A key component of the collaborative project was promotion of STSC. Sessions were audio-recorded, transcribed, and assessed using qualitative research methods with the aid of Atlas Ti software (ATLAS.ti Scientific Software Development GmbH, Berlin, Germany). Two primary investigators studied the transcripts for themes related to STSC. Using an iterative approach, selected themes were explored, and representative quotes were selected. Barriers to promoting STSC fell into broad themes of implementation, institutional, and familial factors.The main challenge identified in implementation was defining a clinically stable eligible population of patients. Key institutional factors were education and motivation of staff. Familial factors involved facilitation and sustained motivation of mothers. In response to these barriers, opportunities for promoting STSC were enacted or suggested by the group, including defining clinical stability for eligibility, facilitating documentation, strategies to increase parent and staff education and motivation, and encouraging maternal visitation and comfort. Our findings may be useful for institutions seeking to develop policies and strategies to increase STSC and breastmilk feeding in their NICUs.
[Click Here for Paper]
Intent vs. Implementation--Food Allocation to Adult Males in WIC Households
Revise and Resubmit at the Journal for Nutrition and Health
The intent of the Special Supplemental Food and Nutrition Program for Women, Infants and Children (WIC) program is found in its name—to increase the health status of a targeted group through supplemental food. Households often contain multiple members who are categorically ineligible, including older ineligible children and adult males. This paper focuses on potential spillover of benefits to adult males. Comparing multiple outcomes across treated and untreated households, I find evidence that consumption of certain WIC foods is higher among men in WIC households compared to the most appropriate comparison group: income eligible non-WIC participants. I also find evidence that this difference is attributable to food-sharing and not an income effect as there is no increase in the consumption of other, non-WIC foods. The increased consumption of cereal, milk and juice is only remarkable among married men in WIC households and not among single fathers. Corollary evidence looking at the differences between married and single women’s food consumption suggests that food is siphoned from the mother and not from the children; this finding supports the altruistic parent food allocation hypothesis. Multiple outcome measures beyond food consumption are analyzed; men in WIC households consume less protein and calories. Most of the results are not robust to full controls, indicating that unobservable propensity to consume WIC foods may be driving entry into the program. If the findings of this study are a true representation of WIC implementation, policy makers should weigh whether this outcome is desirable in terms of the program mission.
[Click here for Paper]