We can't say it often enough: if we have only an index entry or an abstract of a record, we need to find the original record, because the index or abstract may contain mistakes and it is likely to have left out some pieces of information that were in the original. Genealogists who take the easy way out and rely on indexes or abstracts are not only failing to meet standards but also may be creating their own brick walls.
The other day I was busy wallowing in derivative sources and realized that there are more dimensions to this question. I was trying to identify a J. W. Smith family living in Joplin Township, Jasper County, Missouri, in 1880, and had little luck backtracking them in previous censuses. Eventually I came across Ancestry.com's database, "Jasper County, Missouri Deaths 1878-1905."
My search for "J. W. Smith" (exact, in this database produced a remarkable result:
|Name:||Mrs. J. W. @ Smith|
|Age or Birthdate:||abt 78|
|Death Date:||14 Jun 1908|
I was pleased to see that this person was about the age I was hoping to find. As a result, I didn't spot the oddity about this entry right away, but you probably did! When I did notice it, I looked to Ancestry's explanation of the source for this database. Ancestry says it came from two compilations by Kenneth E. Weant of newspaper death notices in the county, one volume 1878-1899, and another 1899-1905.
Obviously this information did not come from where Ancestry said it did. (I will say right now that I have long criticized Ancestry's shoddy quality control and will continue to do so, even though in some cases poorly cited and poorly organized online data are better than nothing. But this post is not about Ancestry's lack of commitment to genealogical excellence, except as to the additional research skills it requires of us.)
Fortunately I was working at the Allen County Public Library Genealogy Center, and I was quickly able to locate the volumes Ancestry had drawn on. In addition to the two the on-line giant named, there is a third: Kenneth E. Weant, Jasper County, Missouri, 6957 Deaths Reported in & Chronological Index to Selected Articles from The Joplin Daily News Herald 1 January 1906 to 31 December 1910 (N.p.: privately printed, 2002). Mrs. J. W. Smith appears on pages 100 and 294 of this book.
One mystery down. But you may well wonder why Mrs. J. W. Smith, with such meager information, appears twice in the book. The answer is that not all derivative sources are created equal. When Ancestry turned the book into an on-line database, it chose to omit a good deal of information that Mr. Weant had collected.
Mr. Weant also tells us that either Mrs. J. W. Smith or (more likely) her husband was a military veteran. (That's what the @ sign signified, as explained in the book but not in the online database.) In addition, Mr. Weant gives the date of newspaper publication and list of the specific newspaper microfilms he consulted and where to order them from. He also includes for most people a de facto partial abstract of relationships mentioned in the obituary: Mrs. J. W. Smith was named as the mother of Mrs. J. W. Cole and sister of Mrs. Mary Keane.
For my purposes that day, this was enough to tell me that Mrs. J. W. @ Smith was not likely of interest to my research. But if I were to seek out the original record(s) here, in particular the published obituary, it would be a lot easier to do by going back systematically from Ancestry's data entry to its (unmentioned) source, because that source (Mr. Weant's third volume) is one step closer to the original and contains a lot more information than Ancestry troubled itself to reproduce -- just as the original obituary may contain its quota of useful information that Mr. Weant left out.
Harold Henderson, "Methodology Thursday: working with derivative sources," Midwestern Microhistory: A Genealogy Blog, posted 25 September 2014 (http://midwesternmicrohistory.blogspot.com : viewed [date]). [Please feel free to link to the specific post if you prefer.]