Brief experimental analysis (BEA) is frequently used to drive intervention selection decisions for students in need of intensive reading fluency intervention. Researchers have demonstrated that most BEA results for students with reading fluency difficulties are undifferentiated when considering the standard error of measurement (SEM) of curriculum-based measurement reading (CBM-R) passages. When confronted with this situation, practitioners must rely on some other characteristic of interventions to drive selection decisions. Considering intervention efficiency alongside effectiveness may be one way to inform selection decisions in the face of undifferentiated BEA results. The current study was undertaken to determine how frequently BEA results are undifferentiated when considering the SEM of CBM-R passages and demonstrate how efficiency data may be considered in tandem with effectiveness data to inform intervention selection. One-trial brief experimental analyses (OTBEAs) consisting of three reading interventions and a control condition were conducted with 14 1st through 11th (M = 4th) graders in the southeastern region of the United States. Results indicated the confidence interval of the most effective intervention overlapped with that of the control condition 50% of the time and that of a more efficient intervention 37% of the time. Limitations and future directions are also discussed.