Armstrong participated as a member of a joint research group including the Center for Health Design and Palomar Pomerado Health in San Diego, California. The goal of this research was to evaluate the effects of flooring and ceiling choices on Corridor Activity Noise, and its perception by both patients and healthcare professionals for 2 material choices: 1. corridors with carpet and standard acoustical ceilings, and 2. corridors with hard flooring and high performance acoustical ceilings. This work was managed jointly by the PPH and CHD, the acoustic measurements were taken by CMSalter Associates, and materials and some data analyses were provided by Armstrong. Test results showed that substitution of a hard surface flooring material for carpeting resulted in a net increase in corridor noise levels with the expected patient and medical professional perceptions of increased annoyance and distraction. However, if the hard surface flooring is combined with a high performance acoustical ceiling, then the rise in noise due to the floor surface is negated with the added absorption of the improved ceiling, such that the result is equivalent in level and perception by both patients and staff.