Whether a digital primary source collection is available through a commercial vendor or freely available through a cultural institution, take time to assess what you will find in that digital collection.  Here are some questions to ask as you explore the collection:

• What is the name of the commercial entity or cultural institution that compiled and published the digital primary source collection?
• If a commercial entity created the collection, what are the institutional (e.g., libraries, museums, etc.) and/or governmental origins of the primary sources in the collection?
• Does the website for the database indicate the decision-making process for inclusion/exclusion of sources?  If so, what is explicitly stated as being included and excluded? 
• Are the objects digitized copies/surrogates/facsimiles of analog originals, or were they “born digital?”
• What are the dates of coverage of the primary sources?
• How does browsing the database by topic differ from keyword searching?
• What types of primary source materials does the database contain on your topic?
• What are the strengths of the database and what evidence illustrates this about your topic?
• What omissions/gaps/absences/limitations exist on your topic, and why might they exist?