Is the name Edward or Harold? 1910 &1920 Census

While doing the summary for Henry Dodd Bigelow and adding his list of children I came across a problem. A few weeks ago I found the birth certificate for an Edward Bigelow (b 1902)that was clearly the son of Henry and Margaret (Minnie) Bigelow. I joyfully assumed that I had found a child that I didn't yet have record for.

The other night I was looking more closely at the census records and saw that in the 1910 Census there is not an Edward listed but there was a Harold M age 8 which would put him also being born in 1902. The 1910 Census also lists the number of children vs the number of children living. These numbers were both 3. This leaves me to conclusion that Harold and Edward are likely the same person but what happened to warrent a name change and is there any way to prove it?

Also Harold is proving a bit elusive in the 1930 Census.

1910 Illinois Census:
Census Taken: 22 April 1910

Name: Henry D Bigelow
Relationship to Head: Head
Male/White
Age: 39
Married 1
Years Married: 14
Number of Children: 3
Number of Children Living: 3
Birthplace: Illinois
Birthplace of Father: New York
Birthplace of Mother: New York
Language Spoken: English
Trade: Engineer
Industry: (Illinois) Rail Road
Read/Write: Yes
House: Own/Morgaged

Name: Minnie E Bigelow
Relationship to Head: Wife
Female/White
Age: 40
Married 1
Years Married: 14
Birthplace: Ireland
Birthplace of Father: Ireland
Birthplace of Mother: Ireland
Language Spoken: English
Trade: None
Industry:
Read/Write: Yes

Name: John C Bigelow
Relationship to Head: Son
Male/White
Age: 13
Single
Birthplace: Illinois
Language Spoken: English
Read/Write/School: Yes

Name: Amerson R Bigelow
Relationship to Head: Son
Male/White
Age: 11
Single
Birthplace: Illinois
Language Spoken: English
Read/Write/School: Yes

Name: Harold M Bigelow
Relationship to Head: Son
Male/White
Age: 8
Single
Birthplace: Illinois
Language Spoken: English
Read/Write/School: No/No/Yes




1920 Illinois Census:
Date Census Taken: January 13th 1920

Name: Henry D Bigelow
Relationship to Head: Head
House: Owned/Free
Male/White
Age:49
Married
Read/Write: Yes
Birthplace: Illinois
Birthplace of Father: New York
Birthplace of Mother: New York
Trade: Engineer
Industry: Locomotive

Name: Minnie E Bigelow
Relationship to Head: Wife
Female/White
Age:49
Married
Read/Write: Yes
Birthplace: Arkansas
Birthplace of Father: Ireland (Spoke English)
Birthplace of Mother: Ireland (Spoke English)
Trade: none
Industry:

Name: John C Bigelow
Relationship to Head: Son
Male/White
Age:23
Read/Write: Yes
Birthplace: Ohio (I know this to be incorrect)
Birthplace of Father: Illinois
Birthplace of Mother: Ireland (contradicts info given above)
Trade: Clerk
Industry: Railroad

Name: Amerson R Bigelow
Relationship to Head: Son
Male/White
Age:21
Single
Read/Write: Yes
Birthplace: Indiana
Birthplace of Father: Illinois
Birthplace of Mother: Ireland

Name: Harold M Bigelow
Relationship to Head: Son
Male/White
Age:17
Single
Read/Write: Yes
Birthplace: Illinois
Birthplace of Father: Illinois
Birthplace of Mother: Ireland