A recent communication by Randzio [Thermochim. Acta 398 (2003) 75] was highly critical of the design and operation of a new commercial instrument used to carry out pressure perturbation calorimetry (PPC), and questioned the accuracy of data obtained from the instrument. Each of the technical objections by Randzio on design and operation is rebutted in this communication and data are presented to support the performance and accuracy of the instrument. Direct comparison of coefficients of thermal expansion measured by PPC with corresponding values obtained by density measurements on well-defined systems shows excellent agreement between the two methods within the accuracy of the density data. In our opinion, there is no evidence to support Randzio's criticism of the instrument's design, operation, or accuracy. (C) 2003 Elsevier B.V. All rights reserved.