test cases and test results it is easy to identify affected parts of the source code if tests fail. Furthermore, redundant test cases can be identified and eliminated. A more complete overview of development activities supported by traceability and their relevance is given in. Practical use of traceability information Extensive studies document the effectiveness, but also the difficulties of capturing traceability information: Traceability accelerates and improves development activities - A study with 71 subjects who performed source code changes with and without traceability support showed benefits of traceability. Developers completed tasks with traceability support 24% faster and 50% more correct. More complete traceability helps avoid software defects - In an analysis of development data from 24 medium-sized and large open-source projects, a statistically significant relationship between the completeness of the captured traceability information and the defect rate of the developed source code was found. Components with more complete traceability showed a lower number of defects (aka bugs). Achieving compliant traceability is difficult - An analysis of the pre-market testing of software in medical devices at the US Food and Drug Administration (FDA) in 2013 identified significant gaps between prescribed and filed traceability information. The quest towards a standard-conformable traceability often results in a "Big Freeze". Big freeze, since companies aim to avoid further development because re-certification is associated with enormous effort. Visualization of traceability information One goal of traceability is to visualize the relationship between artifacts. As the number and complexity of trace links increases, techniques for traceability visualization are necessary. A visualization can include information about the artifacts (e.g. artifact type, metadata, attributes) and links (e.g. link type, metadata, link strength). Common visualizations for traceability information are matrices, graphs, lists, and hyperlinks. Traceability matrix – A traceability matrix is a table-like representation that maps artifacts of one type (e.g., requirements) depicted in columns to artifacts of another type (e.g., source code) depicted in rows. Cells visualize a trace between two artifacts if filled or a non-trace if left empty. The advantage of traceability matrices is that all links between artifacts are visible at a glance. Filters help to reduce the amount of displayed information. Traceability matrices are suitable for management tasks. However, in industry, projects often consist of thousands of artifacts: the tables could become very large and confusing. Traceability graph – In a traceability graph artifacts are represented as nodes. Nodes are connected by edges, if a trace