Helpful hint if you know enough about a family and know they lived in a given city but can’t find them.
I knew the family lived in a given city in NY State, I had them on the 1915 NYS Census and the 1930 Federal Census (same city) but I couldn’t find them in the 1920 Federal Census.
Using the Ancestry search site I;
1 - Used JUST the first name of one sibling and unchecked the exact match for the last name. 2 - I included the birth year (+/- 2 years) 3 - I included the county/state of residence 4 - I included the parent’s name and unchecked the exact match.
After running the search I found that somebody changed the spelling at the beginning of the last name, and when I looked at the information of the record everything matched up, (father, mother, four siblings, correct ages and living at the correct address)