Assessment of Achievement and Growth by Vertical Scaling: Comparison of Vertical Scaling Methods

In this study, item response theory-based vertical scaling was conducted, and the vertical scaling results obtained by using calibration methods and proficiency estimation were compared. The obtained vertical scales were evaluated according to the criteria of grade-tograde growth, grade-to-grade variability, and the separation of grade distributions. For this study, the data was simulated by R program. According to the results, the mean differences in both the methods of concurrent calibration and separate calibration methods increased compared to the levels observed in 8th grade, and that the largest value was obtained through the EAP method. The mean differences obtained through separate calibration were lower than those obtained through concurrent calibration. When standard deviation values were compared, it was observed that the largest values were obtained through EAP in both calibration methods, and that the standard deviation values obtained in both methods were generally close to each other. When effect size values were examined, in both calibration methods, the effect size values increased toward the 8th grade. The effect size values obtained through separate calibrations were lower than those obtained through concurrent calibration. The results generated by all three proficiency estimation methods were similar to