Identifying proper measure to monitor students' growth and understanding characteristics of growth patterns between different achieving groups are critical issues in terms of screening students at risk. To deal with this, we explored relationships of slopes and intercepts between word identification (ID) and passage reading fluency (reading aloud) measures in grade 2 to give answers to (1) What are the characteristics of growth patterns for the high, average, and low achieving group? (2) Do the intercept and the slope of word ID predict those of reading aloud? and (3) Do the three groups show different relation patterns between the measures? A total of 449 second graders in an Oregon school district were chosen, and two measures were administered for three time points. Latent growth modeling was applied to examine the growth patterns and the relationships between the intercepts and the slopes. The results were as follows: (1) the growth pattern in the low-achieving group was both low intercept and low slope. (2) The slope of word reading fluency was not a significant predictor of the passage reading fluency slope in the average achieving group; however, in the low-achieving group, all the paths were significant. These suggest (1) the slope would be an insufficient indicator in decision making based on the progress monitoring scores and (2) for the low achieving group, the word ID measure can be a good indicator of growth in reading for primary graders. Implications for the research and practice in the use of curriculum-based measurements for screening nonresponders are discussed.