Advantages of using existing data:
- The cost and time demands of gathering existing information are generally low.
- You may find high-quality data, gathered in a sound way by experts, covering a much larger geographical area or sample size than you could have tackled yourself.
- The data may have been collected at different points in time, so you can use it to establish a baseline and discern a trend.
- The data could be broken down in such a way that you can easily supplement it with additional evidence of your own.
Source: CAFOD, Christian Aid and Trocaire (2007) Monitoring Government Policies: A toolkit for civil rights organisations in Africa: p.50.