How accurate is FamilySearch? How to check an index against the original record

Most family research now begins with an index: a line on a website that gives a name, a year, a place and a pointer to a record. Anyone who asks how accurate FamilySearch is, or Ancestry or MyHeritage, is usually asking about that line. Indexes make millions of pages of registers searchable, and most of their lines are right. The trouble is that a line in an index looks as certain as the record behind it, and the two are different things.

This guide explains how far to trust each part of the large sites, tells how the example on this site withdrew an identification once the original was read, and sets out the steps that keep a wrong ancestor out of a family tree.

What an index is, and what it is not

An index is a list made from records, usually by volunteers or archive staff, so that the records can be searched. It copies a few facts from each entry: the name, the date, the place, sometimes the parents.

The record itself is the page the clerk wrote at the time, with every column he filled in, the margins, the signatures and the later notes. An index points to a record. Only the record says what was written.

How errors get into an index

Most index errors come from reading, and they are easy to make:

• Old handwriting and faded ink, where a T reads as a P or an M.
• Records in another language. From 1868 the registers of Russian Poland, the Jewish ones among them, were kept in Russian, so a name written in Cyrillic letters had to be read and spelled again in Latin ones.
• The calendar. The Russian state used the old Julian calendar, twelve days behind ours in the 1800s and thirteen from 1900, so a register entry in Russian often carries two dates, and an index may give either.
• Columns read in the wrong order, so a witness or a parent becomes the child.
• Names that vary in Jewish records: a Hebrew name and a Yiddish or civil form for the same person, a patronymic in place of a surname, and children registered under their mother's surname when their parents had married only in a religious ceremony, which is common in the records of Galicia.

Online trees are copies of other people's conclusions

A family tree on a genealogy site shows what its owner decided, with or without a record behind it. When one tree is copied into another, the mistake is copied too, and a wrong date or parent can turn up in dozens of trees that all seem to agree.

Agreement between copies is not evidence. Look for the record each tree cites, and read that.

A correction from the example

In the research for the example on this site, the Tarko family history, an index of Polish Jewish records listed a birth in 1896 for a Nuta Tarko. It looked like a find. Natan Tarko, the father of the family in the book, went by Nuta in Poland, and by his own account he was born in 1895. The name was right and the year was one off, which is common in records of that time.

The original register told a different story. The entry read Nuta Marko. The index had read the M as a T, and Nuta Marko was another man. The identification was withdrawn, and the book does not use the entry. The same correction is the example for step five of How we work, reading and checking.

What the book now says about Natan's birth shows the method from the other side. In 1945 he gave his date as 3 March 1895 and his town as Przedbórz, with his parents' names, and his later papers repeat the date. The records of the Łódź ghetto give dates between 22 February and 29 March 1895, and his refugee forms of 1948 and his American papers give Łódź as his birthplace.

The Jewish registers of Przedbórz for 1895, kept in Russian and now online through the Polish State Archives, were read for the weeks after his date, and his birth is not among them, so it may have been registered late. The book follows his own date of 1945, because it is the earliest record and was given with his parents' names. It also says what is still to be read: the yearly indexes at the back of the Przedbórz registers.

How to check a record, step by step

A careful researcher follows these steps for every person in a tree. They take longer than accepting an index line, and they are the only way to know.

1. Find the original image behind the index entry, on the site that holds it or in the scans of the archive that keeps the register, or write to the archive.
2. Read every column of the entry, including the margins and any notes added later, and transcribe it in full before deciding what it means.
3. Match the parents' names. A child with the right name and the wrong parents is someone else.
4. Match the place and the dates against a second record made at a different time, such as a marriage, a census page or a later document the person gave.
5. Look for a third record made for a different purpose, so that the facts do not all rest on one informant.
6. Write down what the record does not show: a missing mother's name, a date that does not fit, a town that is spelled two ways.
7. Record where the original is kept, with the register, the year and the entry number, so that anyone can find it again.

Tips for checking family tree information online

Open the source attached to each fact before accepting it, and treat a fact with no source as a question. Watch for a person whose dates or children seem to belong to two people of the same name, a common error in shared trees. Keep your own notes of what you checked and where, apart from any tree on a website.

The Genealogical Proof Standard

Professional genealogists in the United States work to a written standard, the Genealogical Proof Standard, set out by the Board for Certification of Genealogists in its book Genealogy Standards and explained at length in the work of Elizabeth Shown Mills, including Evidence Explained. It asks for five things before a conclusion counts as proved, and the steps above are the same standard in plain terms:

• reasonably exhaustive research;
• complete and accurate citations of the sources;
• analysis and correlation of the evidence;
• resolution of any evidence that conflicts;
• a written conclusion that explains the reasoning.

When records disagree

Records often disagree, and a good family history says so instead of choosing quietly. In the example, the mother of the family, Laya, has five different birth dates across her papers. In 1945 she had given a younger age, as many young people did that year, and the younger age stayed on some of her papers.

The book sets the five dates side by side and tests each against the births of her sisters. Only 1928 fits between the sister born in July 1926 and the sister born in October 1929, so the book follows about 1928 and gives its reasons. It also names the records that would settle the question, the Piotrków birth registers of 1927 to 1929, which have not yet been read.

One man, five spellings

Names change from record to record, and each spelling has to be searched in turn. Natan Tarko appears under five forms in the records used for the example:

In Poland he was Nuta, the Yiddish form of his second name, Neta. Four of these records are shown as images on How we work.

How accurate are FamilySearch, Ancestry and MyHeritage?

The fair answer is that each site holds three kinds of material, and each kind deserves a different level of trust.

FamilySearch and its Family Tree

FamilySearch is free with an account, and many of its collections include the images. Some images can be seen only at a FamilySearch center or an affiliate library, or on a partner's subscription site, under limits usually set by the archive that owns the records. Its indexes were typed by volunteers.

Its Family Tree is one shared tree that any registered user can edit, with one profile meant for each person who has died, so each fact in it is only as good as the source attached to it.

Ancestry and MyHeritage

Ancestry and MyHeritage are subscription sites with large collections of images and indexes. Their record images deserve the same trust as any copy of an original, and their member trees and suggested matches the same caution as any tree.

Find a Grave

Find a Grave is a collection of memorials created by volunteers. A photograph of the stone is good evidence of what is carved on it. The typed dates and the linked relatives are someone's reading, and can be wrong.

DNA estimates answer a different question

Many people who ask how accurate Ancestry is mean its DNA ethnicity estimate, an estimate of where a person's ancestors may have lived, drawn from comparison with other people's samples. It says nothing about which record belongs to which ancestor. A DNA test for Jewish ancestry can point to living cousins, whose papers may lead back to records.

What each record can and cannot prove

A gravestone photographed with its Hebrew read and translated is shown on Inside a book. A published family history of another branch is a printed genealogy, and needs the same checks.

What is still unknown

A family history that has been checked against the originals ends up with open questions, and it should say what they are. The example closes with a section that sets out each question, what is known, and which record in which archive might answer it, so a reader can see which conclusions are firm.

When to ask for help

Some of these records can be searched from home. Others are held by archives that answer only written requests, in Polish, German, Russian or Yiddish, and some files have never been indexed at all, so checking them can take months of letters and fees. Doing the research yourself or commissioning it sets out how families decide.

A Zichronos commission includes that work and its archive, copy and translation fees, and ends in a finished book. Every identification in the book is tested against the original record, and the book says which record settles it and what is still unknown. How the example was researched follows the method from the first papers to the printed book. The examples page shows what a finished book holds, what a family history book costs compares the options, and How we work sets out the eight steps. For letters in Yiddish or Hebrew, see how to get old letters read and translated, and for more on the records themselves, finding family records.

Sources: FamilySearch's help article on image restrictions; the Board for Certification of Genealogists, Genealogy Standards; Elizabeth Shown Mills, Evidence Explained; JRI-Poland and the Polish State Archives' Szukaj w Archiwach on the registers of Russian Poland; Find a Grave; the example's notes. Checked October 2026.