Simultaneous measurement of reading growth, gender, and relative-age effects: many-faceted Rasch applied to CBM reading scores.

Reading growth, gender effects, relative-age effects, and reading probe difficulty for reading were simultaneously assessed on one linear scale. The reading measure chosen was the Curriculum Based Measurement (CBM), words-read-correctly. A sample of 1619 students in Grades Two through Seven was employed. There is growth in reading within all grades but decreasing growth with increasing grade level. There are consistent gender differences favoring girls but the differences are equivalent to only one month's growth. There is no consistent evidence of a relative-age effect across grades. Two strategies for linking data across grades were compared and found to produce results consistent with each other and individual grade results.