What is a significant source of error in progress monitoring?

A significant source of error in progress monitoring is measurement error from poorly conducted Curriculum-Based Measurement (CBM) probes. When these probes are not conducted correctly, they can yield inaccurate data regarding a student’s performance. For instance, if the administration of the probes is inconsistent or if the conditions under which they are administered vary significantly from one instance to the next, the data collected will reflect these inconsistencies rather than the student’s true progress. Poorly designed or executed probes can fail to accurately capture the skills being measured, leading to misunderstandings about a student's growth and the effectiveness of instructional interventions.

In contrast, inconsistent data collection methods, while they can introduce errors, are often more of a broader systemic issue that affects the overall monitoring process rather than being directly tied to a specific measurement tool like CBM. Individual student learning styles might impact how a student engages with materials but do not fundamentally alter the reliability of the progress monitoring measures themselves if they are administered correctly. Teacher biases can influence interpretations of results or instructional decisions, but the core measurement issues arise primarily from how well the probes are designed and implemented. Thus, measurement error specifically tied to poorly conducted CBM probes stands out as a major source of error in progress monitoring.