Background: Recent efforts to study quality improvement (QI) efforts to improve the effectiveness and efficiency of healthcare have raised important questions about ethical boundaries for waiving informed consent. Confusion exists because similar projects can be undertaken for research or QI purposes, a distinction currently used to define Institutional Review Board oversight. However, patients are not aware of such distinctions. We sought to evaluate patients' views of waiving consent for non-invasive projects to improve healthcare quality and delivery. Methods: We developed a 32-item measure of patient thresholds for waiving consent for different types of QI interventions, including those involving changes to: 1) the hospital environment; 2) hospital policies or procedures; 3) objects used by patients; 4) medications or devices; and 5) use of patient information. In a sample of 200 hospitalized patients, we tested and confirmed the reliability and validity of subscales representing each of the 5 intervention types. Results: For each of the five consent threshold scales, all items in each scale had substantial item-to-total correlations with the other items in that scale taken together. All five internal consistency reliability coefficients exceeded.70 for the total sample. Means for all 5 scales indicated general patient support for waiving consent across all categories of interventions studied. However, patients were significantly less comfortable foregoing consent for interventions involving medications or devices, or sharing of patient information. Conclusion: We developed and tested a survey instrument to contribute to the understanding of patient preferences for consent in QI assessment activities. Measures were found to be reliable and valid. Findings indicated general patient support for waiving consent across all minimal risk categories studied. However, more work is needed to reassure and protect patients during minimal risk studies involving medications or devices, or the sharing of patient information.