Al-Hikmah University Journal

The study determined the precision with which Senior School Certificate (SSC) Physics practical examination items measure proficiency in Physics practical and estimated the proportion examinees’ ability precisely measured. It also determined the extent to which the examination measure the same theoretical construct among students as well as its reliability The study adopted the descriptive survey research design. The study's population comprised all Senior Secondary Three (SS III) students offering Physics in Osun State during the second term of 2017/2018 academic session. The study sample consist of 631 students chosen using a multistage sampling technique. The NECO 2018 SSC physics practical examination items were used to collect relevant data for the study. The Standard Error of Estimate (SE), limited-information fit measure, and empirical reliability were used to analyze the collected data. The results showed that NECO physic practical examination measure examinees proficiency in Physics practical skills with low precision. However, the ability scores of the examinees were estimated high precision. The results also showed that 88.6% of the examinees fitted the model used in the calibration of the data. Further results showed that the construct validity of the NECO test was low but with a high reliability. The study concluded that the practical examination measures examinees’ practical skills proficiency with low precision and low construct validity. across sub-groups. It is therefore, recommended that examination bodies ensure construct validity and measurement precision during item construction.