Data quality refers to when data is appropriate for its intended use in decision making, planning and operations of the organisation. Data is deemed to be of high quality if it correctly represents the real-world construct for which it is defined. Consistency of data is paramount to the quality of data.
Although the quality of data can be improved after a system is fully implemented through a process of cleansing the data using various tools or bespoke development, this can be avoided by the correct analysis of a business and associated design of the database system that applies the business rules discovered through the analysis.
Ensuring data quality is an on-going process and procedures and rules need to be built into the database and system to ensure that the quality of data is maintained, either at real-time or using scheduled batch process.