Genealogy notes

Records only exist if someone cared enough to create and maintain the records.

Not everyone has been or ever will be recorded.

Records are only searchable online if someone cared enough to undertake the digitisation task.

Accuracy will vary and many digitisation tasks are incomplete or erroneous. Having only a single matching record available online does not prevent an improved match being unrecorded, lost or not searchable online.

Abbreviations and transcription errors are common in hand written records.

Results in transcribers recording

James T
            Williams

instead of James R Williams, or Thos Will as Thomas Williams.

Frequently, connections are made because a possible match exists, albeit with incomplete data.

There is always a risk of someone else being the correct match, with unrecorded details, and this must be assessed. Census records and marriage certificates can be the most helpful here, providing dated evidence of links between people. Deliberate deception cannot be avoided.

Infant mortality complicates family history up to and including the Victorian period, as well as short adult lifespans due to dangerous industrial workplaces.

Relatively poor parents had many more children than may be expected from a modern viewpoint, between seven and thirteen children was common, reusing the same names after death was also common.

Stillbirths and deaths in infancy

Tuberculosis, cholera or typhoid can cause the same first name to be reused multiple times in the same family; Evan David, born in August 1803, had a brother Evan David born in October 1804. What the records did not show, at first, is that the first child died before the second was born.

Evan and Ann David (nee Daniel) tried three times to name a son after his father. Evan David was born 1803 and died at a few months old. A second Evan David was born in 1804 who also died as a child. A third Evan David was born in 1819 who lived to 69 years but appears not to have married or had children. The name was carried on by his great grandson, Evan Emlyn David.

WikiTree contributors, "Evan David (abt.1783-1869)," WikiTree: The Free Family Tree, : accessed 03 October 2026).
WikiTree don't knowingly copy information that's owned by someone else. If we ourselves want to preserve a copyright, we're clear about what's copyrighted so others don't accidentally copy it.

Entire family lines could die out when no children survived into adulthood.

Possibly as a result of the mortality rates, it was also not uncommon for mothers to start having children when they were 14 or 15 years old in the hope that the mother herself would survive long enough to see her children marry.

When combined with errors in dates of birth, nicknames, the tendency to name children after a parent, estimates of the ages of children in some records and other factors, it is easy to lose the first child entirely and assume that the birth date of the elder child is recorded as that of the first.

Genealogy software can make this worse by highlighting the three Evan David brothers described above as potential errors in consistency checks. Until all the data is found, the temptation is to prune the tree to fix the reported error, deleting real people in the process.

It was common for a son to marry a woman with the same first name as one of his own sisters, quite possibly very similar in age.

Marital status, middle names or maiden names are not always recorded, so this can also lead to errors. It can be particularly hard to link the correct mother with her natural children from surviving records.

Common names make all searches harder, along with other ambiguities like approximate dates.

Original records can be affected by poor handwriting, casual abbreviations or unfamiliarity with local traditions, making unusual names harder to match.

Official birth and death records collate data from villages and towns into administrative areas which are unlikely to match current borough or county boundaries.

These will change in the future as well, so include the date and let the tree preserve the original names and boundaries.

Street names and areas disappear or may be renamed as part of redevelopment, so current maps are often misleading.

Census records

Census records are a snapshot of a single day. Anyone staying overnight at a different address is typically excluded from the census at their main residence.

Census records in the UK only go back to 1841. The type of data recorded changes with each census.

Names which become socially embarrassing, or politically dangerous, to younger generations can be dropped or changed without official records.

Some changes can be subtle, some can be deliberate actions to hide the links between individuals.

All records are subject to a non-zero risk of inadvertent destruction, and not only in times of war or family peril.

War does cause sudden and seemingly unlikely relocations. Combined with the lack of census records during wartime and gaps in other records, tracing individuals on either side of a war can become impossible. Some duplication can occur as a result.

Once the records from personal experience are exhausted, judgements are required to include someone on partial knowledge.

It is the links with other parts of the tree which strengthen the tree itself. Only once new people are integrated can the records be found which corroborate or exclude the new people.

Different people will make judgments in their own way.

So the same people recorded in two different family trees could show variations due to any of these judgments by the maintainer of either tree.

Density

The more people are added to the tree, the harder it can be to identify errors and restructure the tree to fix issues.

The thinner the tree, the fewer matches show up in the research due to the lack of data for each person in the tree, so the more likely it is that incorrect data will be added.

Often data on one family member shows up only as a side effect of the records relating to a sister, brother, parent or child.

It is common to find that the records for one parent stop abruptly at the father of the bride or groom.

Shame

Prior to modern civic record keeping, some families would actively ignore wayward children or marriages to those who may be deemed shameful or disreputable. In ways akin to records of conquest, whoever controls the family records controls how, and if, some members of that family are recorded.

Human behaviour does not fit strict social or legal rules, especially regarding the age of becoming a parent.

Rules also change over time. People do marry the sister of their own widow. Two brothers do marry two sisters. People often change their name and / or their entire backstory when emigrating to a new country, whether to escape retribution, persecution, or to make it easier to assimilate. It is common to falsify age records to gain admission (or avoid conscription) into military forces. Some family records will perpetuate convenient stories to hide events which were deemed shameful at the time.

Christening and baptisms

Avoid interpreting the date of christening or baptism (or any similar ceremony) as the absolute date of birth. Ceremonies can take time to organise, especially in rural areas, and one ceremony may embrace several births. The only reality is that birth ceremonies happen after a birth, rarely on the day of the birth and not before birth. It is, however, not rare to have a ceremony after a stillbirth. Many records omit the actual date of birth, only the date of the ceremony.

Including data from another family tree is usually a one-time process.

Any updates of the source are usually not reflected in the trees which imported the original errors.

All genealogy tools interpret these risks in different ways.

Merging data is complex.

Genealogy notes

Missing data and errors are inevitable in all family trees. Errors accumulate as family trees link into each other. These are some common errors and reasons which I have seen (and probably missed) in my own family tree work.