This article reviews the measurement physics of macro and micro Vickers indentation testing and the factors that determine measurement precision and repeatability. Study results show that when force loads of less than 100 gf are used, it is difficult for operators to precisely determine the position of the indenter tip, leading to various measurement errors. These errors explain the data anomalies reported in the literature for low-load Vickers hardness testing, which are often incorrectly attributed to material characteristics.