There are several kinds of indices that you can find online when you are doing genealogical research. Let me explain the issues that we see.
The first problem with almost any index is transcription errors. An index is a secondary source, transcribed from a primary source. Transcription errors are easy to make, but when you cannot see the original to verify, it is impossible to tell if the index is correct.Old handwriting can be difficult so it is always better to have the original to study.
The second problem is that an index almost never includes all the information on the original document. If you have participated in any indexing of records through Ancestry.com or Family Search.org, you know that you key in only selected fields. Those selected fields may not include the information we need to successfully prove a lineage.
Here are some examples:
· Index of recent documents such as the California Death Index: Generally, if you find an event listed in one of these indices of recent occurrences, you can be certain that an actual certificate for the event exists and can be ordered. These indices are generally databases of the original documents that are on file. We depend on the actual long form certificates for more than just the date and place of the event. Since the most important part of a lineage application is making the link between generations, we depend on having the information on the names of the person’s parents and often the name of the spouse. The original document should always be requested when an event is found in an index like this.
· Index of historical records such as the Ohio Marriages database on FamilySearch.org: Mose indices of this type are transcriptions of very old records, often from microfilm. The original images will someday be digitized, but they are not yet. As indicated above, only selected fields from the original record have been indexed which may or may not include what you need. For the collections on FamilySearch, the original microfilm number is usually at the bottom of the page. You can use the website to request a copy of the microfilm at your local Family History Center where you can view and print a copy of the original record.
· Social Security Death Index (SSDI): Not everyone will be included in the SSDI - the deceased person must have collected benefits to be included and not every death gets reported. The only data element that can be reliably collected here is the date of death. The location is where the last check was mailed, not where the person died. For more detailed information, you can send in a request for the original Social Security application, the SS5. That document will include date and place of birth and the names of the person’s parents, all key information for proving a lineage.
Indices can be very useful records, but they should mainly be used as clues to help you find the original records that you need to prove your lineage. There are times that the original records no longer exist and the index is all we have. In such cases, make sure you include the title page of the index book or collection and a copy of the introductory text that explains the circumstances of the transcriptions and the fate of the original records.