Tracing ancestors when two people have the same name

It happens all the time. You go searching merrily along and find your ancestor in every census, in the BMD (birth, marriage, and death) index, and you feel pretty proud of yourself. Then, wham! Suddenly SKS (Some Kind Soul in Internet-language) tells you the John SMITH you're so happy about is their relative, not yours at all. And then you scratch your head and wonder how it all went so wrong.

How to track two people who are about the same age

This advice uses an English example, but like most of my examples, I hope the lessons might be just as good for other countries.

It's not usually a big problem trying to distinguish between people with the same name but from different generations. The age difference makes it pretty easy to know if you've got the right ones.

But when there are two (or even more) people about the same age, with the same name, you have to unravel them carefully. If you want to do it without buying any birth, marriage or death certificates, you're probably going to have to work a little harder.

John CORKER, b. 1862 in Manchester, Lancashire, and his namesake born around the same time

The John CORKER I'm interested in was the son of William CORKER and Mary Ann (nee KNOWLES).

One problem I'm having is that I cannot find him in the 1871 census. This is important because he was young and the facts – his age, name, date and place of birth – are more likely to be correct because those events have a very good chance of being fresh within the memory of the person who gives the information to the census-taker.

Because it's proving difficult to find the family in 1871, I am going to have to look at 1881. I want to find "my" John CORKER and the one with the same name and similar place and date of birth, so I can start making notes of the points where they differ, and where they are the same. I want to build up a little checklist for telling them apart.