Precision position sensing is required for many microscopy techniques. One promising method, back-scattered detection (BSD), provides position sensing at the level of several picometers, and is compatible with platforms that have restricted optical access (e.g. magnetic tweezers, atomic force microscopy, and microfluidics). However, widespread adoption of BSD may be limited by recent theoretical modeling that predicts diminished signals under certain conditions. In BSD the position of a micron-sized bead is measured by back-scattering a focused laser off the bead and imaging the resulting interference pattern onto a detector. Theoretical modeling of the detector response assumes the bead acts as a Mie-Debye scatterer and creates a first order interference pattern in the back-focal-plane of the collection lens. According to this Mie-Debye scattering model the BSD signal reverses sign many times for bead radii between 100 nm and 2000 nm and that for some radii (e.g. 1000 nm) the BSD response would be vanishingly small, limiting the applicability of BSD. We directly measured the BSD response while varying the experimental conditions, including bead radius, medium refractive index, and numerical aperture of the objective. Contrary to the proposed theory, we find that the signal increases with bead radius. Furthermore, the signal sign does not fluctuate, as predicted, over the tested parameters of radius, numerical aperture, and medium refractive index. We conclude that BSD provides a viable signal in a plurality of conditions.