Patient safety is a major concern in today's healthcare; therefore, development of a competent workforce is of utmost importance. Literature reflects insufficient number of studies related to telemetry monitoring competency of nurses. This study determined the reliability and validity of a telemetry monitoring competency tool developed by the author using psychometric theory principles of measurement. The data analysis showed the tool has good content validity with CVI scores of 0.89 and 0.99 using Lawshe's (1975) and Lynn's (1986) methods, respectively. For inter-rater reliability, the tool...