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Library Research Guides
Trinity College
Library & Information Technology Services

Finding and Using Data

Define Your Topic

  • Be as specific as possible when defining your topic.
    • I need annual Gross Domestic Product (GDP) data for the United States, France and Germany for the last 20 years.
    • What is the average SAT score by race for the last 10 years?
  • Identify key concepts and scope, including unit of measure, time frame, frequency and geographic coverage. 
    • Protip: Look at how previous researchers use data related to your topic. Use databases in your field to identify relevant articles, books, studies, etc. Then, use the bibliographies from these sources to identify data sets that might help shape your topic.

Define Your Unit of Analysis

Geographic Unit

  • Local: city agencies

  • National: federal agencies, research centers

  • International: international organizations

Note: Not all data is available at the geographic level you need. Some data is only available at the state or county level.


  • Annual

  • Quarterly

  • Monthly

  • Daily

Note: Some frequencies may need to be calculated.

Unit of Analysis

  • Individual Level

  • Institutional Level: company, health facility, school

  • Production Level: automobiles, commodities

Time Series

  • Cross sectional: collected at the same point of time for several individuals.

  • Longitudinal/Panel: data collected at a sequence of time points for each of a sample of individuals.

  • Time Series: data collected at a sequence of time points, usually at a uniform frequency.

  • Pooled cross sectional time series: mixture of time series data and cross-section data.


(Adapted from: