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lassical Test Theory (CTT) and Item Response Theory (IRT) approach the evaluation of self-esteem measures in distinct ways, emphasizing different aspects of psychometric properties.  According to DeVellis (2006), the primary purpose of Classical Test Theory (CTT) is to evaluate the reliability and validity of total scores derived from measures such as self-esteem scales. CTT operates on the assumption that an individual's observed score is a combination of their true score and random error. Reliability within CTT is often assessed using methods such as Cronbach’s alpha, which examines the internal consistency of items within the self-esteem scale. While evaluating item-level performance, CTT assumes that all items contribute equally to the total score ( DeVellis, 2006). Furthermore, it presumes uniform difficulty across all items, treating them as equally impactful in measuring the intended construct. According to Meguellati et al. (2024), Item Response Theory (IRT) represents a more accurate and comprehensive approach by analyzing individual responses to distinct items independently, yielding precise estimations of latent abilities. IRT investigates the functioning of individual items across varying levels of self-esteem, assessing each item's characteristics based on difficulty and discrimination parameters.  Furthermore, IRT offers detailed reliability information across different levels of self-esteem, providing enhanced precision for both high and low self-esteem scores. Its adaptability is particularly noteworthy, as IRT facilitates the development of adaptive testing, enabling items to be tailored to a respondent’s self-esteem level for greater efficiency and measurement accuracy. In conclusion, Classical Test Theory (CTT) provides a straightforward method for assessing self-esteem measures at the test level, emphasizing overall reliability and validity. In contrast, Item Response Theory (IRT) offers a more detailed examination of item-level properties, yielding precise and nuanced insights into the measure's performance across varying levels of self-esteem. Both methodologies possess distinct strengths and are often used complementarily to enhance the development and evaluation of psychometric instruments.  Reference DeVellis, R. F. (2006). Classical test theory. Medical care, 44(11), S50-S59 Meguellati, S., Samia, A., Ferhat, A., & Djelloul, A. (2024, October 23). A critical analysis of the use of classical test theory (CTT) in psychological testing: A comparison with item response theory (IRT). Hi Kevin, Nice start! Since IRT focuses on item details an