Research instruments are tools used to collect data in a study, such as questionnaires, tests, interview schedules, observation checklists, and rating scales. The quality of data obtained from these instruments depends largely on their reliability and validity. Reliability refers to the consistency and stability of the instrument, whereas validity refers to the extent to which the instrument measures what it is intended to measure. Assessing both reliability and validity is essential to ensure accurate findings and meaningful interpretations. Reliability is assessed through several methods. One of the most common methods is the test-retest reliability method. In this approach, the same instrument is administered to the same group of respondents on two different occasions. The scores obtained are then correlated. A high correlation indicates that the instrument produces stable and consistent results over time. This method is suitable when the characteristic being measured is relatively stable. Another method is parallel or equivalent forms reliability. In this method, two different versions of the same instrument, designed to measure the same concept, are administered to the same respondents. If the scores from both versions are highly correlated, the instrument is considered reliable. This method reduces the effect of memory that may occur in test-retest reliability. Split-half reliability is another widely used technique. The instrument is divided into two equivalent halves, such as odd-numbered and even-numbered items. Scores from the two halves are correlated to determine internal consistency. The Spearman-Brown prophecy formula is often used to estimate the reliability of the