Timelines show the events of your ancestor’s life and where those events occurred. They can be important to direct your research and when you hit that brick wall (which you inevitably will), to focus on what might be missing. They show migrations allowing you to make sure you’re looking in the correct location for the records. They may also help you to distinguish two individuals of the same name. The first thing you should do is pull out and re-read all of your records on the target individual. Sometimes you'll find that information you found years ago, and which didn't mean anything at the time, might provide a clue to solve your research problem. Use this, along with your genealogical software/online family tree to create your timeline.
The genealogical software I use (Reunion), creates a timeline from the events that have been entered. I save the document and open it in a spreadsheet. I like having the information in a spreadsheet because it's easy to sort on different columns and to add new events. If you use an Ancestry online tree, the overview will provide a timeline (although I've found no easy way to export it to a timeline without re-typing the information). Most other software will also provide some type of timeline. The columns I use are: Age, Event, Location, Date, Source and Comments. I've added some additional columns to some of my early timelines.
While researching James Crofoot (above), I had identified him in the 1800 census in Newtown, Connecticut. When I looked at my information on James in a timeline, I discovered that in 1801 James was living in Salisbury, Connecticut, as identified in a land document, and in an 1832 affidavit for a Revolutionary War pension for his brother-in-law, Moses Tuttle, he stated that he knew him 40 years ago (1792) in Woodbury, Connecticut. This made me rethink the 1800 census record I had found. Originally it had seemed logical as the family had been lived in Newtown and Redding for many years, but it led me to other documents confirming that the James in Newtown was a different person.
Another use of timelines helps to narrow down the timeframe when searching for a record. I didn’t know when Michael Daly emigrated to the United States, other than he came through Ellis Island (1892-1924). There were 177 Michael Dalys in the Ellis Island database so how to determine which one was mine? By looking at a timeline of information I had collected on Michael, I new that in 1901 he was in Ireland (1901 census) and that he married in 1912 in Stamford, Connecticut. Also, he did not appear in the 1911 census of Ireland so that limited my search to the timeframe of 1901 - 1911 (and the number of Michael Dalys to about 80). By adding his birth year (± 2 or more years since the Irish were notorious for not knowing this information) I got down to 16 possibilities. The additional information collected on immigration documents as well as naturalizations after 1906 (including the town he was from and his mother’s name), helped me isolate and confirm my Michael Daly arriving 3 April 1909. The spreadsheet below shows the update after I discovered the departure and arrival in the US.
Another hint on timelines can be the birth of the children of a couple which can show the migration pattern of the family by showing when they were in specific locations. When looking for a locality in Ireland for a client, I discovered that one of the sponsors on the baptismal certificate of his child (in Oswego, New York) was a married sister. In researching the sister, I discovered from the 1855 New York State Census that she was married in Ireland and her first three children were born there, the fourth in Oswego. I now had a timeframe for her emigration and based on the age of the oldest child, a timeframe for the marriage. Even though this was a common name, I had corroborating evidence (the names of her spouse and children) and was able to find both her marriage and the baptism of her children in Ireland which gave me the location of the family.
I also add historical events to my timelines. Was your ancestor the correct age to have served in a war? If your ancestor was born between 1872 and 1897 and lived in the United States (whether a citizen or not) you should have a World War I Draft Registration (and if he lived long enough to register for the World War II draft, that gives even more information). If your ancestor was an immigrant don't forget to add historical events from the country of origin. Have you studied the history of Ireland and if you know the location, the history of the locality? This could provide information on the push/pull immigration forces that might have caused them to leave. In your comments field, add the names of sponsors and witnesses to see if the names repeat. If you haven’t been using timelines, give them a try. They may help to solve a longstanding research problem and break through a brick wall.
I'm teaching a class at Family Tree University on Irish Research which begins today. It's self paced for two weeks and it's not too late to sign up.