Try the search tools at stevemorse.org and locate the the census
enumeration district, then read through all the pages until you find
their address. If you can't find the street, or their street number
you will know they were skipped by the enumerator.

If you haven't used this method before, start here
http://stevemorse.org/census/quiz.php

According to a message posted here several months ago, the 1940 census was
undercounted by about 7.5 million people.

It wouldn't surprise me that there are many transcription errors as well
but using the method above, you will know for sure if their street was
included and they were missed, or if there was a transcription error.

Lisa Lepore
llepore@...
Mendon, MA