Visualizing surgical quality data with treemaps.

BACKGROUND: Treemaps are space-constrained visualizations for displaying hierarchical data structures using nested rectangles. The visualization allows large amounts of data to be examined in one display. The objective of this research was to examine the effects of using treemap visualizations to help surgeons assess surgical quality data from the American College of Surgeons created the National Surgical Quality Improvement Program database in a quick and timely manner. STUDY DESIGN: A controlled human subjects experiment was conducted to assess the ability of individuals to make quick and accurate judgments on surgery data by visualizing a treemap, with data hierarchically displayed by surgeon group, surgeon, and patient. Participants were given 20 task questions to complete involving examining the treemap and comparing surgeons' patients based on outcomes (dead or alive) and length of stay days. The outcomes measured were error (incorrect or correct) and task completion time. RESULTS: 120 participants completed 20 task questions for a total of 2400 responses. The main effects of layout and node size were found to be significant for absolute error, P < 0.0505 and P < 0.0185, respectively. The average judgment time to complete a task was 24 s with an accuracy rate of approximately 68%. CONCLUSIONS: This study served as a proof of concept to determine if treemaps could be beneficial in assessing surgical data retrospectively by allowing surgeons and healthcare administrators to make quick visual judgments. The study found that factors about the layout design affect judgment performance. Future research is needed to examine whether implementing the treemap within a dashboard system will improve on judgment accuracy for surgical quality questions.

Visualization of near-optimal sequence alignments.

MOTIVATION: Mathematically optimal alignments do not always properly align active site residues or well-recognized structural elements. Most near-optimal sequence alignment algorithms display alternative alignment paths, rather than the conventional residue-by-residue pairwise alignment. Typically, these methods do not provide mechanisms for finding effectively the most biologically meaningful alignment in the potentially large set of options. RESULTS: We have developed Web-based software that displays near optimal or alternative alignments of two protein or DNA sequences as a continuous moving picture. A WWW interface to a C++ program generates near optimal alignments, which are sent to a Java Applet, which displays them in a series of alignment frames. The Applet aligns residues so that consistently aligned regions remain at a fixed position on the display, while variable regions move. The display can be stopped to examine alignment details.