At the very first stages of your literature review, start taking notes on potential data sources.  Make a habit of jotting down the data used in each study you read to make it faster when you come back later in your search for data.  Also, this practice can help you see and articulate how your contribution is unique.  You might want to keep these notes in a table like the following for easy reference.

See an example of this practice in action:

1. Outline the parameters of your own inquiry (unit of analysis, geography, time period, frequency).
2. Consider who is likely to collect data on this question? Researchers, government agencies, NGOs, IGOs, think tanks?  Would they share these data and are these accessible?
3. If you don't know the answer to #2:
   • Review the sources mentioned in the literature you have read.
   • Refer to compendia like the U.S. Statistical Abstract.
   • Refer to major depositories of data and surveys like the NCES or ICPSR's ____.

These search strategies are outlined at the:

• Data, Datasets, and Statistics Library Research Guide.
• This Data Reference Worksheet is designed to help you brainstorm search strategies.