The following table reports the results of an industry survey of sources of data quality problems.
| Source | Percentage |
|---|---|
| Data entry by employees | 76 |
| Changes to source systems | 53 |
| Data migration or conversion projects | 48 |
| Mixed expectations by users | 46 |
| External data | 34 |
| System errors | 26 |
| Data entry by customers This includes typographical errors and information typed into the wrong fields made when entering data into forms on the World Wide Web. |
25 |
| Other | 12 |
| Source: Wayne W. Eckerson, Data Quality and the Bottom Line: Achieving Business Success Through a Commitment to High Quality Data, The Data Warehousing Institute, 2002. | |