The PDQ-8 is a widely used 8-item patient-reported health outcome measure in Parkinson’s disease (PD) research and practice. However, rigorous testing of its measurement properties is lacking. This paper reports observations from an Rasch based examination of the PDQ-8 using data (n=1289) from the Swedish national registry for PD. The mean (SD) person location was -1.30 (0.91) logits. The estimated reliability was 0.68. All but one items had disordered thresholds and item fit residuals ranged from -3.26 to 4.99, and there was DIF by age (two items) and sex (one item). Residual correlations revealed local dependence (LD), which was dealt with by merging items into two subtests (four items in each). Subtests showed a mean (SD) person location of -0.98 (0.7) logits, reduced reliability estimate (0.58), ordered response categories, improved fit residuals (≤±0.47), and DIF by age for one subtest but no DIF by sex. These observations confirm the importance of considering LD when testing rating scales before drawing further conclusions on their measurement properties. In the case of the PDQ-8, resolving LD improved several aspects of its measurement properties but revealed inferior reliability and targeting remained suboptimal. Together with unclear construct validity, this challenges its appropriateness as an outcome measure.