<p>Situated statistical reasoning is fundamental to health education and research. However, it remains underexplored in the Latin American context, resulting in a scarcity of quantitative evidence to support its theoretical dimensions. This article focuses on the design and validation of a measurement instrument for situated statistical reasoning among postgraduate students. Utilizing theoretical frameworks for situated cognition and adhering to standards for educational and psychological assessments, a 27-item multiple-choice test was developed, comprising adapted and newly created items based on validated instruments. In a field test conducted during the 2022-23 academic year, 165 postgraduate students from the health sciences at a Colombian public university participated in the assessment. The results presented include descriptive statistics of the sample and the psychometric properties of the measurement tool, specifically its reliability and validity. The instrument demonstrated high reliability, with an overall Cronbach’s alpha and omega coefficient of 0.82 and 0.87, respectively. This research defines situated statistical reasoning as it applies to postgraduate students in the health sciences and provides a validated assessment for this construct. The research enriches the fields of mathematics and statistics education by providing empirical evidence on the statistical processes integral to the situated statistical reasoning of health sciences students.</p>