In the big data era, huge amounts of data are being collected as a result of the day-to-day operation of organisations. While this increased availability of data brings potential value to organisations and society it also brings challenges. The usefulness or quality of this data and accounting for that quality in data driven decision making is a concern. Relevant problems associated with the quality of data include missing data, incorrect data, and the inclusion of outliers. The specific nature of these problems impacts on how the data is improved and its quality dealt with. Available methods ...