Census takers weren't known for their impeccable handwriting, so you can understand why transcribers occasionally misread names and entered them incorrectly into databases. Unfortunately, that means an ancestor named Robert Cordes, for example, could show up as Robert Cordis or Cordos or some even stranger misspelling — and unless you try the right one, you won't find him. Luckily, Ancestry.com and other sites let you search some spelling variations automatically, using Soundex.

The 1880, 1900 and 1920 US censuses — plus parts of the 1910 and 1930 censuses — are indexed according to the Soundex system, which is based on sounds in surnames. (Although the federal government developed this indexing system for the census, several organizations have adopted it for their own databases. That's why you'll find the Soundex-search option for other census years.) Every surname gets a four-character Soundex code (such as G516), beginning with the first letter of the surname. The remaining three characters are taken from the name sequentially, ignoring the letters a, e, h, i, o, u, w and y (see the key at right). Letters with similar sounds (such as b, p, f and v) are represented with the same number. You'd code as one digit any adjacent consonants from the same category (such as dd or sc). Once you reach the four-character limit, ignore the remaining letters. If you run out of key letters before reaching that limit, add one or more zeros. So the code for Cordes is C632 — as for Cordis and Cordos.

Select the Soundex option on Ancestry.com to search for all names with the same code as the surname you've entered. A Soundex search for Cordes will turn up matches for Cordis, Cordos, Curtis, Curtiss and other names. Of course, you'll have more results to wade through, but you're less likely to miss your ancestor.

From the April 2005 Family Tree Magazine