You will discover all manner of errors, alternative spellings, uses of nicknames, and other insidious challenges in your research. Many things cause errors to be included in any family trees. Once an error is published in any format, less thorough researchers use the erroneous information and it is therefore perpetuated to other researchers. This is especially true in the Information Age when errors are published in online family trees, electronic mailing lists, online message boards, Facebook page postings, and other social media. That means that each and every piece of information you encounter must be tracked down and personally examined for accuracy. More about locating original evidence is discussed later.

All information published in family trees should be suspect. The same thing holds true for family histories, regardless of who compiled and published them and when  The author may or may not have been a competent researcher, and so you will also want to retrace the facts they presented and personally examine and analyze the evidence. The author of the work may have encountered two people in the same vicinity with the same name. It is possible to have taken a wrong turn and researched an incorrect person and their antecedents. The creator of the history may have facilitated the process of retracing their research by including source citations for some or all of the evidence included. However, it is essential for you to obtain an exact copy of the original documentary evidence and personally analyze it to check the veracity of the research. If source citations are provided, take advantage of obtaining the most original copy of the source document possible for your personal evaluation and analysis.