regression model could be used to adjust for differences between ACS and CCD estimates based on demographic and other variables that were available from the CCD.
Precision, Intertemporal Stability, and Timeliness
To evaluate precision, intertemporal stability, and timeliness, the panel concentrated on the BRR because it is stability of reimbursement that is of greatest importance to school food authority directors. For ACS estimates (direct and model-based), the primary measure of precision is the sampling error, as measured by the standard error.40 Because they are based on a larger sample, the 5-year ACS estimates for a district will have smaller sampling error than the 3-year or 1-year estimates. However, this greater precision comes at a price: a 5-year ACS estimate reflects the average observed over a 5-year period, and thus will be relatively slow in adjusting to real changes in the economy. Trade-offs between stability and timeliness are assessed by comparing the year-to-year variability in BRRs computed using CCD certification data versus the alternative ACS eligibility estimates (1-, 3-, and 5-year). The BRRs based on CCD certification percentages provide an indication of the year-to-year variation in reimbursement that is normally experienced by and, therefore, will likely be acceptable to districts. Data on school district reimbursements under the school meals programs were not available to the panel, so there is no way to compare ACS estimates with actual reimbursement data.
For the case study districts and schools within those districts, the panel compared BRRs based entirely on distributions of students with BRRs based on distributions of meals served. These distributions and the associated BRRs differ because students in the different categories participate at different rates, with, generally, students receiving free meals having the highest rate, students paying full price having the lowest rate, and students paying a reduced price having a rate between the other two. The BRRs based on the distribution of meals served reflect these differential participation rates, whereas the BRRs based entirely on the distribution of eligible or certified students take no account of participation. Comparing the BRRs illustrates how a district would generally be underreimbursed if participation were not taken into account in developing claiming percentages.
40 Standard errors were provided by the Census Bureau for all ACS direct and model-based estimates.