Using the Castle Garden Index
I have used the Castle Garden Index to find information on immigrant ancestors. Over the years I have encountered several oddities which will be treated separately.
1. The index contains data that does not appear on the most readily available copies of microfilmed passenger lists from New York. This suggests that the index was prepared from some other unidentified source material. Where is this material located? If you know the answer, I'd like to hear from you.
Justification: The National Archives has a database of "Germans to America" where I found a couple of Stenzel families I am interested in. For both families, they list a destination city of Chicago. When I look at the original passenger list on film (series M237) for Johann Stenzel, that fact is NOT included (nor are certain other indexed facts). This suggests that the Germans to America index was created from a more detailed type of record. A baby was born on the voyage of Johann Stenzel and his wife but the baby is not found on the film even at the end of the listing. The Germans to America lists an "unknown" of that surname who I would gather is that baby.
2. The index includes data for other ports of entry besides New York such as Baltimore, Boston, New Orleans, and Philadelphia. This is not explicitly stated on the Castle Garden site.
Justification: The index turned up a ship name and date of arrival for a family. With that information, I tried to find the list on the filmed New York lists. The ship could not be found! A Google search on the ship revealed it had arrived in Baltimore instead. So that oddity has been resolved.
Digging further, it appears the index at Castle Garden is comprised, in part, with data created by the Center for Immigration Research at the Balch Institute of Ethnic Studies where Germans to America Passenger Data File, 1850 - 1897 is but one of the components. The data was also donated to the National Archives and searchable through their Access to Archival Databases (AAD). The Castle Garden index is easier to use but AAD has more documentation to explain the origins of the data. It also provides a mechanism for downloading search results as a CSV file.
3. Like any indexing project, errors in data entry are made. Neither Castle Garden nor AAD provide a mechanism for correcting errors. In fact, the National Archives flat out refuses to accept changes because, in their view, it would be like changing history. I'm sure this attitude is shared among archive professionals. What they fail to understand is that they are not being asked to change the primary record. An index is a secondary source used to find information in the primary record. Errors in an index make it hard if not impossible to find the original record. Correcting errors or at least adding alternative spellings would make it easier for someone else to find the information they need.
Justificaton: This example is about a census index where the surname Stenzel has been indexed as Stengel. I found the family in the census because I knew their address. The index was no help because the name was misspelled Stengel.