Much of the advice given in the previous question Tracing US ancestor back to Germany? will also apply to this question -- in this answer I will add information specific to immigrants to the US during the early 20th Century.
The first thing I do with any research question is to start with a review of all the records I have collected so far. I make a list of everything I have, either by making a list in my research journal, or by creating a Genealogy Source Checklist like the one demonstrated in this video by Crista Cowan, or both.
Next I extract the information found in the records and I place all the information on a timeline for my research subject, with a note reminding me which source on my list had that information. I refer to Elizabeth Shown Mills' Evidence Analysis Process Map as needed when I apply this information to specific research questions.
As I review my information, I work backwards chronologically from the records which are created most recently to the ones which are the oldest. I do it this way because the picture of a person's life at their death gives us the most complete view of their life. This helps me separate records that may belong to two different people (or more) who may have the same name, living in the same location. (I have one German immigrant family with three generations all living in the same household, so I've learned to be careful.) Knowing about someone's entire life gives you more identifiers to use when examining the earlier records.
I make note of the names of other family members, friends, neighbors, and associates that I find in each record (see Mills' QuickLesson 11: Identify Problems and the FAN Principle for an example of how studying people in a group makes it easier to answer questions about people with common names). For some families, it isn't possible to work backwards to the previous generation using the records of a single person -- you have to fill in gaps by using the records of siblings instead.
As I review the sources, I make a list of research questions that occur to me, and a "records wantlist" of records that might hold more information. For any immigrant who was of the right age to register for the draft in WWI, but was born in Germany, these questions might be:
- Did this person become a naturalized citizen later in life? If so, finding his naturalization papers might give me more information, including the answer to the next question:
- When did this person arrive in the United States?
- Were there other people from his family who arrived on the same voyage?
Each new historical record can yield more information that will help you narrow down when someone emigrated and clarify exactly when he came from. It is always better use the basic principle to start with what you know, and work outwards in small steps, rather than taking big leaps. I also keep in mind the five elements of the Genealogical Proof Standard -- because I want to search widely enough that I don't miss information, and I want to be sure I am understanding and interpreting all the information I find in the right way.
Let's use as an example the alleged birthplace of Magdeberg/Magdeburg.
First, we need to remember -- it is very likely that the person registering for the draft did not write the information down himself -- he dictated the answers to the question to a registrar, who wrote down the answers. The registrar may not have been a German speaker, so we can't take the name of the birthplace at face value.
Using the online Meyers Gazetteer, which is set up for researchers to enter the names without umlauts, I get two results for the spelling Magdeberg:
Mägdeberg, Niederung, Gumbinnen, Ostpreussen, Preussen
Hof (Farm, Manor, Courtyard)
Mägdeberg, Engen, Konstanz, Baden
For Magdeburg with a U, there are more options. It may refer to
StKr. (City with own state government offices), HptSt. of the prussian province of Sa.
Going to FamilySearch's list of abbreviations, we can expand this as follows:
- StKr. Stadtkreis Area included in municipal administration district, as opposed to rural or county government which would be “Landkreis”
- HptSt. Haupt Stadt Capitol city
- Sa. Sachsen(Staat) Saxony, (state)
The Herman A Zimmerman who said he was born on 13 Oct 1896 in Magdeburg, Germany when he registered for the draft in Tacoma City no 2, Washington, United States gives as the name of his nearest relative someone who lives in Prussia -- which doesn't tell us enough in itself to say which place is meant. Consider too that if someone is from a place near a capital city, their birthplace can be misreported as being from the big city instead of the smaller town nearby. I made this mistake about my father's hometown -- I remembered that he was from the bigger city (where he had lived later on in his life) but my older brother knew the name of the smaller town where he had grown up. So even though you have two records that agree, it might help to gather more information. This is where knowing more about the community at large may help -- some Germans during this time period were recruited for their skills in specific industries, and if your grandparents were skilled, there may be other people who were also recruited, giving you even more records to look at for clues.
If these two records were all I had, I would not attempt to leap directly back to Germany. Since his WWI draft card says he was an alien at that time, I would try to locate all his Census records to look for clues in the Census records about his naturalization and his arrival.
If your grandfather naturalized after 1906, or didn't naturalize at all, you might have a rich potential source of information in the records held by the USCIS (the successor agency to the INS). Their website gives an overview of the five different record sets which are available via the USCIS Genealogy Program. The article from Prologue Magazine (Spring 2013), The A-Files: finding your immigrant ancestor, explains what information can be found in an Alien registration (for non-citizens) living in the US between April 27 and December 26, 1940). The examples shown in the article are a good illustration of why we are often advised to work forwards in time, rather than backwards, when we are researching our families.
So when creating a research plan, it helps to set a big goal and then break the research down into smaller, more manageable tasks, keeping in mind what places your grandfather lived, and what records might have been created about him in each time and place. If you are completely new to research The FamilySearch Research Wiki has many articles about the Research Process that can help you get started.