NEMS Measures Development
The objectives of the original Nutrition Environment Measures Study were to:
- Develop measures of nutrition environments and survey retail and food service outlets (stores and restaurants);
- Test the inter-rater and test-retest reliability of NEMS instruments;
- Examine sampling and generalizability issues.
The NEMS measures focus on surveying community and consumer nutrition environments which include the type and location of food outlets, availability of healthful choices and information, pricing, promotion, and placement of healthier food products. The measures are indicators and are not meant to be an extensive inventory of individual food outlets. Since their public release, many researchers and practitioners have used the measures in their own research and communities.
The third aim of NEMS is still in process as more data is collected for the NIK Study (Neighborhood Influences on Kids).
When raters are well trained and quality control is enhanced, the NEMS measures have demonstrated high reliability and validity. Proper training is necessary to ensure proper use of and/or adaptation of the measures.
To assess inter-rater reliability in the study, two trained raters independently visited food outlets to complete the same set of assessments on the same day. To assess test-retest reliability, outlets were re-assessed within one month after the initial observations by one of the original raters who had rated the outlet previously.
The measures were completed in 88 stores and 216 restaurants. The study yielded very high inter-rater reliability, and test-retest reliability ranged from .73 to 1.00 except for measures of fruit quality. Construct (discriminant) validity was examined by comparing the availability of healthful options in grocery stores versus convenience stores, and high- vs. low-income neighborhoods. The hypotheses were confirmed. Findings for measures of restaurant environments were similar.
Sampling and Generalizability
The third aim of NEMS is still in process as more data is analyzed from the Neighborhood Influences on Kids or NIK Study.