Calculating a Possible Birth Date for Jane Darragh

Image by Willfried Wende from Pixabay

 

Trying to figure out a birth date, death date, or range of dates for an ancestor with just a piece of information or two? Perhaps you have a death date and an age on a headstone and want to calculate their birth date. Or maybe you have several censuses with differing ages and are attempting to hone in on the right one.

After watching Carolyn Ladd's excellent RootsTech webinar "Which Date Is Right? Solving Birthdate Conflicts Through Genealogical Analysis," I decided to implement some of her suggestions to tackle determining Jane Darragh's birth date. I have not yet found a birth or baptism record for Jane, so I've had to rely on other sources which give her age, which—typically—vary somewhat from document to document. 

I used some great date calculators on Tony Proctor's Parallax View blog. He included several in his post, "Measurement Tools," published in 2015, with various updates since then. Perhaps genealogists with more experience may already know about these tools, but the ones listed below were new to me and very helpful:

• Calculate range of possible dates given an age
• Analyses the overlap between multiple date ranges
• Offset a base date to find a new date. 

Let's see how I used each.

 

Looking at Jane Darragh's Dates 

To begin, I created a table with all of the dates and ages I had from Jane's sources: 

I used the Calculate range of possible dates given an age tool to determine a range of birth dates, shown in the fourth column, below. When using this tool, there is an optional button to "Remember" each calculation. The "Remember" feature populates the tool Analyses the overlap between multiple date ranges to narrow down the most likely time frame(s) for Jane's birth, based on the ages give in various documents.

 

The Analyses the overlap between multiple date ranges tool gave me the chart below for Jane, noting the ranges of date overlap shown in the red box:

I could immediately disregard most of the last entry for 21 June 1856-20 June 1857; Jane's mother Dorah died on 12 October 1856, so only a fraction of that range could have been a possible window for Jane's birth. Also, if the 1856 dates were correct, Jane would have been much younger in the 1861 census, four years rather than 7 years old. It seems unlikely that someone could mistakenly think a four-year-old was actually a seven-year old, so I find the 1856 dates less likely.

Looking at the bar chart, it's clear there is the most support for the time frame 15 Jan. 1853 to 30 March 1853. This correlates well with the very first census Jane appears in, the 1861 Census of Canada West. There she is noted as age 8 "at her next birthday," meaning she was 7 at the time of the census. Documents created earlier in a person's life seem to be more accurate, as it's easier for informants to remember a child's age versus that of an adult in their 20s or 30s for example.

Using the "Offset a base date to find a new date" tool, I entered Jane's most likely birth date ranges to determine the possible window when she was conceived: 15 April 1852-30 June 1952. This will be helpful in determining her brother Daniel's birth date.

Looking at Daniel Darragh

I used the same tools to look at Jane's brother Daniel's sources to find his birth date range and conception window. Daniel had more sources to work with and they were a bit more consistent in his ages than Jane's were.

The analysis resulted in the following chart with overlap dates in the red box:

In Daniel's case, the most support is for a birth date in the 13 January 1850-30 March 1850 range. This  correlates well with the 1851 Census of Canada West where Daniel is noted as age 2 "at his next birthday." That range also encompasses his age in his death certificate, as well as in the 1851, 1881, 1891, and 1901 Canada censuses, where his ages were remarkable consistent. I feel confident Daniel's birth date was in early 1850.

Using the "Offset a base date to find a new date" tool, I entered Daniel's most likely birth date ranges to determine the possible window when he was conceived: 13 April 1849-30 June 1849.  

 

Considering The Parents' Marriage Date

To date no marriage record has been found for Jane and Daniel's parents, John and Dorah Darragh. However, knowing Daniel was their eldest son, they likely married a year or so before his birth. If Daniel's conception window began about April 1849, the couple likely wed in late 1848-early 1849.

 

A Marriage and Birth Timeline

The following table summarizes the possible dates of John and Dorah's marriage and Daniel and Jane's births. This timeline seems plausible. There is a gap of about two years between Daniel's birth and Jane's conception which appears to be in keeping with a common two-year spacing between children in this era.

When vital records are missing, we must use the other sources to determine important dates as best we can. Censuses, death certificates, and other sources can all be helpful. The calculators on the ParallaxView website allowed me to use these other sources to develop a timeline for the early events in the Darragh family. 

Until next time... 

 

ADDITIONAL RESOURCES

Find additional date calculators on these websites:

• Cyndi's List, Calendars & Dates > Calculators and Converters 
• The Ancestor Hunt > Genealogy Research Tools