Swiss general internal medicine board examination: quantitative effects of publicly available and unavailable questions on question difficulty and test performance.

BACKGROUND Formerly, a substantial number of the 120 multiple-choice questions of the Swiss Society of General Internal Medicine (SSGIM) board examination were derived from publicly available MKSAP questions (Medical Knowledge Self-Assessment Program®). The possibility to memorise publicly available questions may unduly influence the candidates' examination performance. Therefore, the examination board raised concerns that the examination did not meet the objective of evaluating the application of knowledge. The society decided to develop new, "Helvetic" questions to improve the examination. The aim of the present study was to quantitatively assess the degree of difficulty of the Helvetic questions (HQ) compared with publicly available and unavailable MKSAP questions and to investigate whether the degree of difficulty of MKSAP questions changed over time as their status changed from publicly available to unavailable. METHODS The November 2019 examination consisted of 40 Helvetic questions, 40 publicly available questions from MKSAP edition 17 (MKSAP-17) and 40 questions from MKSAP-15/16, which were no longer publicly available at the time of the examination. An one factorial univariate analysis of variance (ANOVA) examined question difficulty (lower values mean higher difficulty) between these three question sets. A repeated ANOVA compared the difficulty of MKSAP-15/16 questions in the November 2019 examination with the difficulty of the exact same questions from former examinations, when these questions belonged to the publicly available MKSAP edition. The publicly available MKSAP-17 and the publicly unavailable Helvetic questions served as control. RESULTS The analysis of the November 2019 exam showed a significant difference in average item difficulty between Helvetic and MKSAP-17 questions (71% vs 86%, p <0.001) and between MKSAP-15/16 and MKSAP-17 questions (70% vs 86%, p <0.001). There was no significant difference in item difficulty between Helvetic and MKSAP-15/16 questions (71% vs 70%, p = 0.993). The repeated measures ANOVA on question use and the three question categories showed a significant interaction (p <0.001, partial eta-squared = 0.422). The change in the availability of MKSAP-15/16 questions had a strong effect on difficulty. Questions became on average 21.9% more difficult when they were no longer publicly available. In contrast, the difficulty of the MKSAP-17 and Helvetic questions did not change significantly across administrations. DISCUSSION This study provides the quantitative evidence that the public availability of questions has a decisive influence on question difficulty and thus on SSGIM board examination performance. Reducing the number of publicly available questions in the examination by introducing confidential, high-quality Helvetic questions contributes to the validity of the board examination by addressing higher order cognitive skills and making rote-learning strategies less effective

Open-Source GIS

The chapter explains the components of which an Open Source GIS is built of. They comprise the core software-component (mapserver), open source geospatial libraries, a typical open source GIS (Quantum GIS), the presently most widely spread open source database (PostgreSql) including its geospatial extension (PostGIS), and an overview over the most important license models. A mapserver can broadly be defined as a software platform for dynamically generating spatially referenced digital map products. The University of Minnesota MapServer or UMN MapServer, or simply MapServer, is one such system. Its basic features are visualization, overlay, and query. The mapserver architecture consists of a client, a server, and a database. The server is split up in three layers, the CGI-layer tying in to the network hardware, the geospatial analysis system, and the communication layer. Client and server do a load balancing for an optimal performance. The architecture is built upon the standards of the Open Geospatial Consortium of which those regarding interoperability are most important. The section concludes with a number of examples. The following section names and explains many of the geospatial open source libraries, starting with GDAL (raster) and OGR (vector). The other libraries are FDO (Feature Data Objects, JTS Topology Suite (JTS), GEOS, JCS Conflation Suite (JCS), MetaCRS, and GPSBabel. The application examples include derived GIS-software and data format conversions. The following section provides a detailed explanation of Quantum GIS, its origin and its applications. The features include a rich GUI, attribute tables, vector symbols, labeling, editing functions, projections, georeferencing, GPS support, analysis, and Web Map Server functionality. The architecture of Quantum GIS comprises a hierarchical set of several layers that ranges from data access via analysis to application. Future developments will address mobile applications, 3-D, and multithreading. The next section is dedicated to the database part. The origins of PostgreSQL are outlined and PostGIS discussed in detail. It extends PostgreSQL by implementing the Simple Feature standard. This allows applying a rich set of geospatial functions such as geometry types, e.g. polygons, relationships, e.g. within, and analysis function, e.g. convex hull. The last part of the chapter explains the most important open source licenses such as the GNU General Public License (GPL), the GNU Lesser General Public License (LGPL), the MIT license, and the BSD license, as well as the role of the Creative Commons

Identification of glacial meltwater runoff in a karstic environment and its implication for present and future water availability

Glaciers all over the world are expected to continue to retreat due to the global warming throughout the 21st century. Consequently, future seasonal water availability might become scarce once glacier areas have declined below a certain threshold affecting future water management strategies. Particular attention should be paid to glaciers located in a karstic environment, as parts of the meltwater can be drained by underlying karst systems, making it difficult to assess water availability. In this study tracer experiments, karst modeling and glacier melt modeling are combined in order to identify flow paths in a high alpine, glacierized, karstic environment (Glacier de la Plaine Morte, Switzerland) and to investigate current and predict future downstream water availability. Flow paths through the karst underground were determined with natural and fluorescent tracers. Subsequently, geologic information and the findings from tracer experiments were assembled in a karst model. Finally, glacier melt projections driven with a climate scenario were performed to discuss future water availability in the area surrounding the glacier. The results suggest that during late summer glacier meltwater is rapidly drained through well-developed channels at the glacier bottom to the north of the glacier, while during low flow season meltwater enters into the karst and is drained to the south. Climate change projections with the glacier melt model reveal that by the end of the century glacier melt will be significantly reduced in the summer, jeopardizing water availability in glacier-fed karst springs