Applied Physics and Mathematics Annotation << Back GEOMETRIC APPROACH TO CALCULATION AND INTERPRETATION OF THE PARTIAL CORRELATION COEFFICIENT IN APPLIED RESEARCH O.V. MAKSIMOVA The paper considers the problem of external factors influencing the correlation of the studied features, which is solved thanks to the partial correlation coefficient. Based on the geometric interpretation of the partial correlation coefficient through the representation of variables as vectors, its formula is derived and a comparison with the usual correlation coefficient is given both in sign and in absolute value. Also shown are cases leading from non-zero correlation to zero partial correlation, thereby causing a refutation of the primarily obtained relationship of features. A demonstration of the obtained properties in research problems of ecology, sociology and sports on natural data of both historical and modern periods is given. In particular, cases are presented when the partial correlation coefficient sign differs from the usual one, which leads to a revision of the qualitative conclusions made on the basis of ordinary correlation. The obtained results allow us to have a visual representation of the partial correlation coefficient, which can improve the understanding of the nature of the relationships of the studied features. Keywords: partial correlation coefficient, Pearson correlation coefficient, geometric interpretation, spurious correlations, hidden factors. DOI: 10.25791/pfim.05.2025.1342 Pp. 28-38.