Purpose: mdplot (medical database plot) visualizes both structure and quality of data in medical databases by means of a summary representation of design and completeness in XML format. The goal is to identify attributes suitable for evaluation and to aid in creating open data models.
Methods: A three-stage visualization approach is applied. First, an overview of all classes in a database, second a detailed view of a specific class and third an analysis of individual attributes. Missing data is identified to enable specific efforts to improve data quality prior to analysis. For each class number of patients, attributes, and records per patient are provided. A condensed bar chart for each category of attributes (categorical, numerical, text and other) visualizes available content: The abscissa corresponds to the sequence of attributes; the ordinate represents completeness per attribute. By selection of a specific class, a detailed description is provided including mean completeness in each category as well as completeness per attribute. To analyse attributes that are collected at several time points per patient, a frequency distribution of records per patient can be generated.
Results: The new methodology was applied to two clinical research databases consisting of 292 attributes (955 patients) and 224 attributes (610 patients), respectively, and resulted in major restructuring of the systems. A public website is provided for generation of mdplots.