We exhibit a strong connection between the matchgate formalism introduced by Valiant and the ZW-calculus of Coecke and Kissinger. This connection provides a natural compositional framework for matchgate theory as well as a direct combinatorial interpretation of the diagrams of ZW-calculus through the perfect matchings of their underlying graphs. We identify a precise fragment of ZW-calculus, the planar W-calculus, that we prove to be complete and universal for matchgates, that are linear maps satisfying the matchgate identities. Computing scalars of the planar W-calculus corresponds to counting perfect matchings of planar graphs, and so can be carried in polynomial time using the FKT algorithm, making the planar W-calculus an efficiently simulable fragment of the ZW-calculus, in a similar way that the Clifford fragment is for ZX-calculus. This work opens new directions for the investigation of the combinatorial properties of ZW-calculus as well as the study of perfect matching counting through compositional diagrammatical technics.

Physician handoff of care is a mechanism for transferring patient information, responsibility, and authority from one set of caregivers to another. At shift change at a hospital, residents going off shift handoff patients to those coming on shift. There are limited handoff of care tools that facilitate the handover process by condensing patient information in reports that can be referenced during the handoff of care and used during patient care as cognitive artifacts. This effort works to address information, data entry and reporting requirements for a resident handoff of care tool that would support transfer of information as well as patient care.

Electronic medical record and separate sign-out system data (code status, location, medications and laboratory results) from 60 patients were compared to assess the impact of parallel data systems. In addition, a survey was administered to 74 Internal Medicine residents to characterize what elements they self-report using in their sign-out system. The survey results indicated that residents use the separate sign-out system to support hand-off of care, but also patient care. The data comparison showed that while code status data matched for all patients, 28.3% of patients had a location entered into the sign-out system that did not match the medical record. 46 (76.7%) patients had a medication reported in the sign-out report that did not match the medical record. Of 180 laboratory values compared, 130 (72%) matched the most recent value or a value within the past 24 hours. Using a criterion of “medically relevant matches”, a test of proportion indicated that significantly more laboratory values agree, thus supporting the hypothesis that physicians are less likely to update data when changes are not medically relevant. To reduce workload and the amount of inaccurate information being passed to physicians, sign-out functionality should be integrated into electronic medical record systems.