In developing the framework and guidelines for calculating data quality measures a work plan was prepared that describes the technical approach for developing the various elements of the framework and guidelines. The following are the major steps in developing the framework and guidelines
Six fundamental data quality measures were identified in the regional Traffic Data Quality workshops namely accuracy, completeness, validity, timeliness, coverage, and accessibility. The various types of data (e.g., original source, archived data), data consumers or users, and broad groups of applications or uses were identified.
Having defined the quality measures, a framework was developed that is applicable to a broad spectrum of application areas. The framework includes the steps and methods to calculate and report and data quality measures taking into consideration (i) data from different sources (e.g., original source, archived database), (ii) different users and customers and users of traffic data, (iii) various applications and levels of aggregation. The methods are illustrated with three specific case study examples.
The guidelines on assessing and measuring data quality include guidance on how data quality interests can be considered in data collection, reporting, and sharing agreements. The following are the main elements of the guidelines.
The draft framework and guidelines were reviewed by a few state DOT representatives and offices of FHWA for review and comments. The state DOTs were expected to apply the framework to the data from actual projects to test the concepts and methodologies contained in the framework. The beta testing was intended to address issues including ease of use, practicality, applicability, costs involved, integration with other state DOT functions, and required enhancements. The beta testing was also intended to validate the estimates of the levels of effort required to establish the data quality assessment system and also validate the straw man estimates of the acceptable data quality targets. Based on results of the beta test, the estimates were revised.
The following chapters present the framework and the guidelines for measuring and reporting traffic data quality as well as the results of the beta testing of the concepts and methodologies.