First in a series of posts.
A discussion of assumptions one might be tempted to make. With examples taken from my own research.
Assumption: Government Documents are Always Reliable
While one might say, "of course they aren't, no one would make that mistake," this is what makes me cringe most often when watching Who Do You Think You Are. The researcher finds the grandmother in a household in a census, and tells the celebrity the parents in the household are their great grandparents. Perhaps their great grandparents are dead, and these are actually the grandmother's uncle and aunt? I assume (hope) the researcher has conducted additional research to verify the information, but they don't mention it on television, leading some viewers perhaps not to ask that question in their own research.
I have distant relatives who have looked at the above US census record from 1870 for the Denyer family, and recorded in online databases Amanda, Sherwood, and Ida as children of Ebenezer and Sarah, despite them being a decade older than William and McAlpin. They are actually the children of Ebenezer's brother, Samuel Denyer, who died in 1861, and his wife Zarelda, who died in 1867. (As a side note, several of the names in this record are actually middle names. McAlpin, for example, is my great grandmother, Margaret Jane McAlpin (Denyer) Vanevery.
Above is a marriage record from the UK General Register Office. The marriage occurred in London in 1902. If I asked you to tell me the name of the Father of the Bride, your answer would be "Nathan Nathan." I'm pretty certain I know what happened. The clerk asked the bride for her maiden name, and then asked only for her father's given name. Unfortunately, it appears Sarah followed the Jewish custom of using her father's first name as her last. Perhaps as an affectation, since it was no longer common in the 1900's. The 1901 UK census indicates the family name was Sandler, and Sandler appears on some documents as Sarah's maiden name.
Just because there is a government stamp on a document doesn't mean the information is necessarily correct. Record the information in your database, and cite your source, but always be open to discovering new, conflicting information.