Where a surname is used by hundreds of thousands, or millions of people, it would be practically impossible to differentiate these persons using national-index data alone.
In some cultures, one-name studies are impossible, since hereditary surnames are not used at all or in the case of names such as Singh may represent religious practice rather than an ancestry.
Since a majority of human societies use patronymic surnames, one-name studies generally focus on male succession and ignore family relationships through marriage.
In most one-name studies, a united lineage will not be discovered, but broad perspectives can be achieved, giving clues to name origins and migrations.
More limited one-name studies can be conducted using other national indexes including: One-name studies are generally rounded out with a miscellany of information drawn from national bibliographies, archival catalogues, patent databases, reports of law cases, tax lists, newspaper indexes and web searches.
For the period before civil registration, in principle back to 1538 in England and Wales and 1533 in Scotland, parish registers have recorded birth and/or baptisms, marriages and deaths and/or burials.
Records for Scotland can be searched at the pay-per-view web site ScotlandsPeople, and this means that a one-name study with a British focus can be conducted from anywhere in the world.
While most one-name studies are conducted as a pastime, rather than as an economic activity, the sheer volume of information to be organised may require semi-professional data-processing and publishing skills.
[citation needed] Many one-name researchers keep data tables in computer spreadsheets because it is possible to see hundreds of items on a single screen and use thinking power to detect patterns.
[citation needed] The Guild of One-Name Studies was established in the United Kingdom in September 1979, and maintains a register of surnames being researched by members.
[5] Traditionally, publication of definitive research is undertaken by printing a book or by publishing a one-name periodical.