Types of Sources for Your Genealogy Research
If you're like most people, you think you know a lot about yourself. How do you know the birth date? You were obviously there, but you weren't in a condition to be a reliable witness. This is where primary sources come in handy. Most likely, witnesses were present who helped create a record of the event.
Primary sources are documents, oral accounts — if the account is made soon after the actual event and witnessed by the person who created the account — photographs, or any other items created at the time of an event. Some primary sources include birth and marriage certificates, deeds, leases, diplomas or certificates of degree, military records, and tax records.
For example, a primary source for your birth date is your birth certificate. Typically, a birth certificate is prepared within a few days of the actual event and is signed by one or more witnesses to the birth.
The timeliness and involvement of direct witnesses makes the information contained on the record (such as the time, date, and parents’ names) a reliable firsthand account of the event. It's important to recognize that just because a record was prepared near the time of an event doesn't mean that every fact on the record is correct.
Typographical errors can occur or incorrect information can be provided to the creator of the record. Often, these errors are not caught when the record is created. For example, in the case of a birth certificate, new parents are preoccupied with things other than government paperwork during their stay at the hospital.
It's always a good idea to try to find other primary records that can corroborate the information found in any record.
Secondary sources are documents, oral accounts, and records that are created some length of time after the event or for which information is supplied by someone who wasn't an eyewitness to the event. A secondary source can also be a person who was an eyewitness to the event but recalls it after significant time passes.
Some records may be considered both primary and secondary sources. For example, a death certificate contains both primary and secondary source information. The primary source information includes the death date and cause of death. These facts are primary because the certificate was prepared around the time of death, and the information is usually provided by a medical professional who pronounced the person dead.
The secondary source includes the birth date and place of birth of the deceased individual. These details are secondary because the certificate was issued at a time significantly later than the birth (assuming that the birth and death dates are at least a few years apart).
Secondary sources don't have the degree of reliability of primary sources. Often secondary source information, such as birth data found on death certificates, is provided by an individual's children or descendants who may or may not know the exact date or place of birth and who may be providing information during a stressful situation.
Given the lesser reliability of secondary sources, back up your secondary sources with reliable primary sources whenever possible.
Although secondary sources are not as reliable as primary sources, that doesn't mean secondary sources are always wrong or aren't useful. A good deal of the time, the information is correct, and such records provide valuable clues to locating primary source information.
For example, in the case of a birth date and birthplace on a death certificate, the information provides a place and approximate time frame you can use as a starting point when you search for a birth record.
You can familiarize yourself with primary sources by collecting some information for your own biographical profile. Try to match primary sources for each event in your own biographical sketch. If you can't locate primary source documents for each event in your life, don't fret! Your biographical sketch can serve as a primary source document because you write it about yourself.
For additional information on primary sources, see Using Primary Sources at the Library of Congress website for teachers.
You will encounter tertiary sources. Tertiary sources are compilations of primary and secondary sources, such as articles found online or in encyclopedias or almanacs.
For comparisons of primary, secondary, and tertiary sources and examples of each, see James Cook University's overview of primary, secondary, and tertiary sources.
Or check out William Madison Randall Library's guide for identifying primary, secondary, and tertiary sources.
For strategies on using primary sources online, see the Reference and User Services Association (of the American Library Association) page.