HD: Food Security (2011)

Citation:
 
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:

To use economic analysis to investigate interaction between Food Stamp Program participation, food security status and the composition of food expenditures.

Inclusion Criteria:

Data were included from households with income less than or equal to 1.3 times the poverty threshold.

Exclusion Criteria:

Data from households with an income greater than 1.3 times the poverty threshold were excluded.

Description of Study Protocol:
  • Recruitment: Data were obtained directly from the 1999 Current Population Survey – Food Security Supplement data
  • Design: Data were analyzed using a quadratic almost ideal demand system with a bootstrapping two-step method of estimation to assess the relationship between Food Stamp Program participation and food insecurity
  • Statistical analysis: See study design.
Data Collection Summary:

Timing of Measurements

Not applicable.

Dependent Variables

  • Food security 
  • Food expenditures (food at home and food away from home).

Independent Variables

Food stamp program participation.

Description of Actual Data Sample:
  • Initial N: 12,071 low-income households.
  • Attrition (final N): N/A
  • Age: N/A
  • Ethnicity: N/A
  • Location: United States.
Summary of Results:

Key Findings

Variables

Coefficient
(Standard errors)

Statistical Significance of Group Difference

Food Stamp Program Participation and Food Security Status

0.58 (0.67)
Not statistically significant

Food Stamp Program Participation and Total Food Expenditure

0.55 (0.09)

P<0.05

Food Stamp Program Participation and Likelihood of Eating Out

-0.52 (0.25)

P<0.05

Cumulative Density Function x Food Stamp Program Participation and Share of Food-Away-from-Home Expenditures
-0.55 (0.13)
P<0.05
Probability of Food Stamp Program Participation and Food-Away-from-Home Expenditures
-0.34 (0.08)
P<0.05
Probability of Food Stamp Program Participation and Food-at-Home Expenditures
0.29 (0.07)
P<0.05

 

  • Food Stamp Program participation does not effect food security status, but it does affect food expenditures
  • Food Stamp Program participation and food security status are endogenous, based on statistical significance of the correlation (P<0.05)
  • Food stamp participation does increase food expenditures of low-income households (P<0.05)
  • Households participating in the Food Stamp Program are less likely to eat out (P<0.05). Food stamp participation decreases the share of food away from home expenditure conditioned on whether the household does eat out (P<0.05).
  • The effects of working adults, especially working adult women, are statistically significant and positive in determining the likelihood of eating out (P<0.05)
  • Conditional on eating out, a one-percent increase in the probability of being a food stamp recipient would lead to a decrease of 0.34% in food away from home expenditures and to an increase of about 0.29% in food at home expenditures.
Author Conclusion:
  • This study did not find any significant effect of the Food Stamp Program on food security status. However, food stamp participation affects total food expenditures and decreases the likelihood of eating out among low-income households.
  • Food Stamp Program participation also has a significant negative effect on food away from home consumption
  • Because the food stamp program participation increased total food expenditures and decreased consumption of food away from home, the researchers concluded that the Food Stamp Program does help meet the needs of persons who are insecure in accessing food
  • The researchers also noted that working status results in increased food expenditures, suggesting that policymakers should consider needs of the working poor when implementing the Food Stamp Program.
Funding Source:
Government: USDA, Economic Research Service
Reviewer Comments:
Quality Criteria Checklist: Primary Research
Relevance Questions
  1. Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies) N/A
  2. Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about? Yes
  3. Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice? Yes
  4. Is the intervention or procedure feasible? (NA for some epidemiological studies) N/A
 
Validity Questions
1. Was the research question clearly stated? Yes
  1.1. Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified? Yes
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? Yes
  1.3. Were the target population and setting specified? Yes
2. Was the selection of study subjects/patients free from bias? Yes
  2.1. Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study? Yes
  2.2. Were criteria applied equally to all study groups? Yes
  2.3. Were health, demographics, and other characteristics of subjects described? Yes
  2.4. Were the subjects/patients a representative sample of the relevant population? Yes
3. Were study groups comparable? Yes
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) N/A
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? N/A
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) Yes
  3.4. If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis? Yes
  3.5. If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.) Yes
  3.6. If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")? N/A
4. Was method of handling withdrawals described? Yes
  4.1. Were follow-up methods described and the same for all groups? Yes
  4.2. Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.) Yes
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? Yes
  4.4. Were reasons for withdrawals similar across groups? Yes
  4.5. If diagnostic test, was decision to perform reference test not dependent on results of test under study? N/A
5. Was blinding used to prevent introduction of bias? No
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? No
  5.2. Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.) No
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? No
  5.4. In case control study, was case definition explicit and case ascertainment not influenced by exposure status? N/A
  5.5. In diagnostic study, were test results blinded to patient history and other test results? N/A
6. Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described? Yes
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? N/A
  6.2. In observational study, were interventions, study settings, and clinicians/provider described? Yes
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? Yes
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? Yes
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? Yes
  6.6. Were extra or unplanned treatments described? N/A
  6.7. Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? N/A
  6.8. In diagnostic study, were details of test administration and replication sufficient? N/A
7. Were outcomes clearly defined and the measurements valid and reliable? Yes
  7.1. Were primary and secondary endpoints described and relevant to the question? Yes
  7.2. Were nutrition measures appropriate to question and outcomes of concern? Yes
  7.3. Was the period of follow-up long enough for important outcome(s) to occur? N/A
  7.4. Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? Yes
  7.5. Was the measurement of effect at an appropriate level of precision? Yes
  7.6. Were other factors accounted for (measured) that could affect outcomes? Yes
  7.7. Were the measurements conducted consistently across groups? Yes
8. Was the statistical analysis appropriate for the study design and type of outcome indicators? Yes
  8.1. Were statistical analyses adequately described and the results reported appropriately? Yes
  8.2. Were correct statistical tests used and assumptions of test not violated? Yes
  8.3. Were statistics reported with levels of significance and/or confidence intervals? Yes
  8.4. Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)? N/A
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? Yes
  8.6. Was clinical significance as well as statistical significance reported? Yes
  8.7. If negative findings, was a power calculation reported to address type 2 error? No
9. Are conclusions supported by results with biases and limitations taken into consideration? Yes
  9.1. Is there a discussion of findings? Yes
  9.2. Are biases and study limitations identified and discussed? N/A
10. Is bias due to study's funding or sponsorship unlikely? Yes
  10.1. Were sources of funding and investigators' affiliations described? Yes
  10.2. Was the study free from apparent conflict of interest? Yes