WD
William Duffy — 1940 US Census Record
Linked across censuses1940 United States Federal Census · Allegheny-County, Pennsylvania
Our Model Tree links this William Duffy across the 1930 and 1940 US Censuses in Allegheny-County, Pennsylvania (XGBoost, ~Confirmed) — first a son (b.~1920), then head of a 6-person household.
Age 20
b. ~1920
Male
Son
Born: Pennsylvania
Single
1940 Census Record Details
| Census Year | 1940 |
| Location | Allegheny-County, Pennsylvania |
| Surname | Duffy |
| Given Name | William |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 20 |
| Marital Status | Single |
| Birthplace | Pennsylvania |
| 1935 Residence (City) | Pittsburgh |
| 1935 Residence (County) | Allegheny |
| Additional Details | |
| Occupation | Laborer |
| Industry | Steel Mill |
| Class of Worker | PW |
| Hours Worked | 24 |
| Income (1939) | 200 |
| Highest Grade | H-2 |
| 1935 Residence | Same place |
| Birth State | Pennsylvania |
| Birth Country | United States |
| Birthplace (normalized) | pennsylvania |
| Occupation | Laborer |
| Township / Ward | Pittsburgh |
| Est. Birth Year | ~1920 |
Household Members
Census records only state relationship to the household head.
Pairwise kinship is derived (~90–95% accurate), not recorded.
Step/blended families and boarders can break it.
6 people recorded at the same address in the 1940 census.
| Name | Relation to head | Relative to William | Age | Birth yr |
|---|---|---|---|---|
| Mary Duffy | Daughter | — | 31 | ~1909 |
| Agnes Duffy | Daughter | — | 22 | ~1918 |
| Catherine Duffy | Daughter | — | 16 | ~1924 |
| William Duffy | Son | — | 20 | ~1920 |
| Margaret Duffy | Daughter | — | 25 | ~1915 |
| Charles Duffy | Head | — | 64 | ~1876 |
Census Appearances
1930
Allegheny, Pennsylvania
Son, age 9
Allegheny, Pennsylvania · implied b. ~1921 — 5 household members
●
Primary link
· ~Confirmed · 2 sources
XGBoost
Household
| Surname | Duffey |
| Given Name | William |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 9 |
| Marital Status | Single |
| Birthplace | Pennsylvania |
| Father's Birthplace | Pennsylvania |
| Mother's Birthplace | Pennsylvania |
| Occupation | laborer |
| Industry | scan tracks |
| Class of Worker | W |
| Can Read/Write | Yes |
| Birth State | Pennsylvania |
| Birth Country | United States |
| Birthplace (normalized) | pennsylvania |
1940
Allegheny-County, Pennsylvania
Son, age 20
Allegheny-County, Pennsylvania · implied b. ~1920 — 6 household members
| Surname | Duffy |
| Given Name | William |
| Relationship to Head | Son |
| Sex | M |
| Color / Race | White |
| Age | 20 |
| Marital Status | Single |
| Birthplace | Pennsylvania |
| 1935 Residence (City) | Pittsburgh |
| 1935 Residence (County) | Allegheny |
| Occupation | Laborer |
| Industry | Steel Mill |
| Class of Worker | PW |
| Hours Worked | 24 |
| Income (1939) | 200 |
| Highest Grade | H-2 |
| 1935 Residence | Same place |
| Birth State | Pennsylvania |
| Birth Country | United States |
| Birthplace (normalized) | pennsylvania |
Model Tree
An inferred pedigree reconstructed from census links — up to 4 generations within the 1900–1950 window. Closer generations are built from household co-residence; deeper ones are bridged by following a relative to their own childhood census. Confidence compounds and weakens with each generation.
Our Model Tree links William Duffy across 2 US Census years (1930 and 1940) in 2 locations, using XGBoost record linkage.
Show:
This person
Anchor record
William Duffy
Son · 1940 · age 20 · b. ~1920 · Pennsylvania
★ You are viewing this record
Sibling
Margaret Duffy
Sibling · 1940 · age 25
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Mary Duffy
Sibling · 1940 · age 31
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Agnes Duffy
Sibling · 1940 · age 22
Source co-child of head (derived)
● Co-child · derived · ~0.88
Sibling
Catherine Duffy
Sibling · 1940 · age 16
Source co-child of head (derived)
● Co-child · derived · ~0.88
Confirmed / household (~0.90+)
Probable / derived (~0.65–0.89)
Candidate (<0.65, unverified)
Original Census Page
1940 US Federal Census — Allegheny-County, Pennsylvania
Open full size
1940 US Federal Census — Allegheny-County, Pennsylvania
Page Contents
40 people indexed on this census page (nara:1940:m-t0627-03664-00537)
| Line | Name | Age | Relation | Occupation | Birthplace |
|---|---|---|---|---|---|
| 1 | Charles Duffy | 64 | Head | Laborer | Scotland |
| 2 | Mary Duffy | 31 | Daughter | Operator | Pennsylvania |
| 3 | Margaret Duffy | 25 | Daughter | — | Pennsylvania |
| 4 | Agnes Duffy | 22 | Daughter | Deliveryman | Pennsylvania |
| 5 | William Duffy THIS PERSON | 20 | Son | Laborer | Pennsylvania |
| 6 | Catherine Duffy | 16 | Daughter | — | Pennsylvania |
| 7 | Annie Corcoran | 70 | Head | — | Kentucky |
| 8 | Charles Reilly | 31 | Head | Brakeman | Scotland |
| 9 | Catherine Reilly | 30 | Wife | — | Scotland |
| 10 | Charlotte Reilly | 12 | Daughter | — | Pennsylvania |
| 11 | Catherine Reilly | 10 | Daughter | — | Pennsylvania |
| 12 | Patricia Reilly | 6 | Daughter | — | Pennsylvania |
| 13 | Frank Blade | 49 | Head | Laborer | W. Virginia |
| 14 | Elizabeth Blade | 48 | Wife | — | W. Virginia |
| 15 | John Privijanska | 50 | Head | Electric Welder | Hungary |
| 16 | Catherine Privijanska | 28 | Wife | — | Pennsylvania |
| 17 | John Privijanska | 9 | Son | — | Pennsylvania |
| 18 | Helen Privijanska | 8 | Daughter | — | Pennsylvania |
| 19 | Harry Today | 56 | Head | Boilermaker | Poland |
| 20 | Mary Today | 38 | Wife | — | Poland |
| 21 | Rose Today | 20 | Daughter | Canner | Pennsylvania |
| 22 | Josephine Today | 1 | Daughter | — | Pennsylvania |
| 23 | Catherine Today | 4 | Daughter | — | Pennsylvania |
| 24 | Charles Popp | 49 | Head | Boilermaker | Hungary |
| 25 | Barbara Popp | 45 | Wife | — | Hungary |
| 26 | Charles Popp | 20 | Son | New Worker | Pennsylvania |
| 27 | Joseph Popp | 16 | Son | — | Pennsylvania |
| 28 | Betty Popp | 14 | Daughter | — | Pennsylvania |
| 29 | Sandor Popp | 50 | Head | Boilermaker | Hungary |
| 30 | Rose Popp | 50 | Wife | — | Hungary |
| 31 | Ethel Popp | 22 | Daughter | Stamper | Pennsylvania |
| 32 | Paul Popp | 20 | Son | New Worker | Pennsylvania |
| 33 | Frank Popp | 17 | Son | — | Pennsylvania |
| 34 | Margaret Popp | 15 | Daughter | — | Pennsylvania |
| 35 | Ernest Popp | 11 | Son | — | Pennsylvania |
| 36 | James Popp | 9 | Son | — | Pennsylvania |
| 37 | Elsie Popp | 8 | Daughter | — | Pennsylvania |
| 38 | Florence Popp | 5 | Daughter | — | Pennsylvania |
| 39 | Ronald Popp | 3 | Son | — | Pennsylvania |
| 40 | Dolly Hanna | 34 | Head | — | Pennsylvania |
Related Census Records
About This Record & Model Tree
This record was independently indexed by YourRoots from the 1940 United States Federal Census (NARA). Our Model Tree links this person across census decades using XGBoost-based record linkage, with per-link confidence scores. Household corroboration strengthens the signal when co-residents appear on the same census pages in multiple years.
Source: National Archives and Records Administration (NARA)