Curriculum-based measurement (CBM) is used to index annual student growth across the primary grades. Procedures and measurement metrics are developed for mathematics, spelling, written expression, and reading. CBM oral reading (CBM-R) rate is the most researched and well established of those available procedures (Wayman, Wallace, Wiley, Ticha, & Espin, 2007). CBM-R is used as an index of reading rate and fluency, which are identified as critical skills to target for instruction and intervention within the early stages of reading development (National Reading Panel, 2000; National Research Council, 1998). CBM-R outcome also functions as a robust indicator of overall reading development throughout the primary grades (Wayman et al., 2007).
CBM-R progress monitoring data are collected and used to evaluate instructional effects, determine when to modify the instruction, and evaluate response to intervention (Deno, 1985, 1986). Teachers who use progress monitoring data are likely to use more specific and measurable goals, rely more substantially on data to guide instruction, and modify instruction more frequently (Fuchs, Fuchs, & Hamlett, 1989; Fuchs, Fuchs, & Stecker, 1989). Progress monitoring applications of CBM-R have the potential to confer the most substantial benefit to students. Progress monitoring can be conceptualized as either interim benchmark/screening assessments when data are collected three to four times per year, or time series continuous assessments when data are collected daily or weekly.
Both interim and time series CBM-R data are plotted graphically and evaluated against goals and goal lines. Fuchs and Shinn (1989) recommended that the rate of expected growth should derive from local normative performance so that individual student achievement can be compared against the local normative performance of grade-level peers. A goal line is established by connecting the CBM-R data point for the observed level of performance from Week 1 (initial performance) to the expected/typical level of performance at Week 36 (ending performance). Once graphed, the goal line provides a graphic trajectory of expected growth for the academic year. Ongoing time series data are then plotted on the graph and evaluated against the goal line. For example, if a student's initial level of CBM-R performance in September was 20 words read correctly per minute (WRCM) and in May that student was expected to read 60 WRCM, then the expected annual growth is 40 WRCM across 8 months, or 32 weeks. That translates to ~1.25 WRCM per week of growth (1.25 WRCM = 40 WRCM/32 weeks). The goal line and trajectory of expected growth is based on the assumption of a monotonic and linear trend.
Monotonic Linear Growth
Standards of expected performance within and across the year provide the foundation to establish instructional goals and goal lines. There are two influential studies that established standards of weekly CBM-R growth (Deno, Fuchs, Marston, & Shin, 2001; Fuchs, Fuchs, Hamlett, Walz, & Germann, 1993), which have application in both research and practice. Fuchs et al. (1993) analyzed a CBM-R data set comprised of 103 students in general education and 14 students in special education. Each student was assessed weekly for an entire academic year using CBM-R procedures. Although some students evidenced a negatively accelerating annual growth, the researchers concluded that annual growth is, on average, monotonic and linear. They also observed a negatively accelerating trend across grades. That is, the rate of CBM-R growth was positive in all grades, but the rate of growth declined in each successive grade. The resulting analysis yielded grade-specific estimates of standard and ambitious rates of growth--and assumed a pattern of monotonic linear growth. Respectively, the growth, determined by the number of WRCM, were 1.5 and 2.0 in first and second grade, 1.0 and 1.5 in third, 0.85 and 1.1 in fourth, 0. …