Towards Valid and Reliable Privacy Concern Scales: The Example of IUIPC-8

Abstract: Valid and reliable measurement instruments are crucial for human factors in privacy research. We expect them to measure what they purport to measure, yielding validity, and to measure this consistently, offering us reliability. While there is a range of privacy concern instruments available in the field and their investigation continues unabated, we shall focus on a brief form of the scale Internet Users? Information Privacy Concerns (IUIPC-8) as an example. We not only present IUIPC-8 itself, but also consider methods for the evaluation of valid and reliable measurement instruments. In this, confirmatory factor analysis (CFA) serves us as a valuable tool. Our inquiry takes into account the ordinal and non-normal data yielded by the IUIPC questionnaire, compares multiple models to confirm the three-dimensionality of the scale, examines global and local fit and, finally, estimates construct validity and internal consistency reliability metrics. We offer a comparison between IUIPC-10 and IUIPC-8 drawing on two independent samples. In conclusion, we highlight properties of the scale and considerations for its use in practice.