Avoiding common mistakes in genealogy research

Start with what you can prove

There is a moment in every family historian's life when a branch suddenly stretches back three more generations. Someone else has already done the work, and their tree is neatly filled in, with dates, places and photographs attached. It feels like a gift. More often than not, it is a trap. Genealogy is not a race to the furthest ancestor; it is the slow business of proving, one small step at a time, that each person in your tree truly belongs there. The mistakes below are the ones I see most often, in other people's research and in my own early notebooks. None of them are shameful. All of them are avoidable, and avoiding them will save you years of unpicking work later.

Unsourced trees are a clue, never a source

Online family trees multiply like dandelions, and the same wrong parents can appear in dozens of them within a season. A tree without source citations tells you only that somebody, somewhere, once believed something. Copy a name and a date into your own file, and you have inherited their error without inheriting their reasoning.

• Treat another person's tree as a signpost, not as evidence. Note the details, then go and find the original record for yourself.
• Favour trees that cite specific records — a baptism entry, a certificate, a census reference — over those that simply state facts.
• Ask whether several trees are genuinely independent. Ten identical trees can all be copying one unsourced original.
• Be especially cautious when a tree solves a difficult problem suspiciously neatly, such as a common surname in a large city.

Names were spelled as they were heard

We are used to surnames with one fixed spelling, but before the twentieth century spelling was fluid, and clerks wrote down what they heard. Your great-great-grandmother may appear as Catherine, Catharine, Catheryne, Katherine and Kitty across five records — and all five may be her.

• Search every plausible variant: Brown and Browne, Smyth and Smith, Davies, Davis and Davys. Say the name aloud in the accent of the place.
• Allow for the phonetic spelling of clergy, registrars and census enumerators, and for names shortened or anglicised after a move from Ireland, Scotland, Wales or overseas.
• Remember that middle names, nicknames and initials can hide a person completely. A man baptised John William may marry as William and be buried as J. W.
• Check place names too: the same village can be recorded under a parish, a hamlet, a chapelry or a nearby market town.

Write down where every fact came from

This is the single habit that separates a reliable tree from an attractive one. A citation is not bureaucracy; it is the note that lets you — or your cousin in twenty years — check the work and trust it. Without it, you will eventually find two conflicting dates and no way to decide between them.

• Record the record type and its date, for example: baptism register, 12 March 1841.
• Note the archive, collection or website you consulted, together with the reference, volume or page number.
• Note who told you, if the detail came from a relative, a letter or a family bible.
• Note the date you looked, because catalogues, indexes and websites change.
• Write down what the record does not say. The absence of a father's name, or of a place of birth, is information in itself.

Dates, ages and other quiet traps

Even when you have found the right record, the information inside it can mislead you.

• In the 1841 census, the ages of adults were rounded down to the nearest five years, so a woman recorded as 40 might be anywhere between 40 and 44.
• Before 1752 the year in England began on 25 March. A child born in February 1700 arrived before a sibling baptised in December 1699, and you may meet double-dated years such as 1700/01.
• People were often vague or untruthful about age, birthplace and marital status, particularly in census returns and on marriage certificates.
• Indexes contain transcription errors. If a search returns nothing, try wildcards, alternative spellings and neighbouring districts before deciding a record does not exist.

Habits that keep a tree honest

The good news is that sound research is mostly a matter of small disciplines repeated patiently. Work backwards in a straight line and resist the urge to leap three generations ahead because a name looks promising. When you hit a wall, record the wall: a note explaining exactly what you searched and what you failed to find will stop you repeating the same fruitless afternoon in three years' time.

• One fact, one source, one entry — no exceptions, however tired you are.
• Keep a research log of searches made and blanks drawn, not just successes.
• Back up your file and store a copy away from your home.
• Talk to living relatives while you can, record the conversations, and label them honestly as family memory rather than proof.
• Revisit old conclusions every few years; new records come online and your own eye grows sharper.

Your tree does not need to be enormous. Forty ancestors you can defend, with their sources attached and their spelling variations accounted for, are worth far more than four thousand you cannot explain — and they will still be standing when the next generation takes up the search.