This mixed methods study used Time-Driven Activity-Based Costing to measure direct value-adding labor in schools participating in the National School Lunch Program. Video-recorded observations, individual interviews, and focus groups were employed. Four types of entrees prepared using similar recipes, ingredients, and methods were studied at five production sites. Bills of activity were developed, and labor capacities calculated. Food, labor, and total costs per meal equivalent and allocated labor costs for each product were determined. Theoretical and practical capacities for each worker, based on information from individual interviews and district records, were calculated.

Twenty-two video recordings were made of workers preparing the entrees. Specific definitions for each production step were developed consistent with the bills of activity. Times for each step were measured and validated. Verbatim transcripts of focus groups, to describe workers' experiences as part of the study, were analyzed to identify themes.

Practical capacity was found to be greater than reported in other industries. Schools' allocated food costs per meal equivalent were similar, but allocated labor costs and meals per labor hour were dissimilar. Production processes comprised two methods, preparation in bulk and preparation in hotel pans.

Production steps fell into five broad categories, accounting for the majority of time in production: adding ingredients, covering/uncovering pans, measuring temperatures, moving product, and stirring. Differences between mean times for steps compared pair-wise across all products and all sites were statistically significant (p < .001) for eight of ten pairs; differences in mean times for the pan production method were statistically significant (p < .001) for nine of ten pairs. Differences in mean times for the bulk production method were not significant. For the entrées , calculated food costs plus the cost of direct value adding labor was on average 6.97% of calculated food costs plus allocated labor, ranging from 0.97% to 41.96%. Analysis of menu items' costs to produce would be more useful if more accurate and complete labor costs were determined, extending the findings of this study.

Focus groups themes found that video recording did not cause discomfort, due to workers' understanding of the study process and trust of the researcher. Recommendations for future research are provided.