I printed out this index page from Ancestry almost two years ago. I haven’t really worked on this family since then, so it’s just been sitting in my file. I’m glad I had a hard copy, though, because otherwise I would have thought I was losing my mind.
This is what the index page looks like today. Same source information, same reference number, volume, and page number. Same everything except now the death date is 1977 instead of 1964.
Commonwealth of Massachusetts, Department of Public Health, Registry of Vital Records and Statists, “Massachusetts, Death Index, 1901-1980,” database, Ancestry (https://www.ancestry.com/ : accessed 4 Feb 2017), James Basquill death 1964, volume 2, index volume 124/125, page 145, reference number F63.M363 v.124/125; citing Massachusetts Vital Records, Index to Deaths, 1961-1965, Aakeson-Chmura, volumes 124-125. Boston, Massachusetts: Commonwealth of Massachusetts Department of Public Health Registry of Vital Records and Statistics. Facsimile edition. Boston, Massachusetts: New England Historic Genealogical Society. Rec. Date: 4 Feb 2017. Cit. Date: 4 Feb 2017.
Always check the original image, if there is one. Always, always, always. This isn’t a great source, given that it’s just an index. It’s several times removed from the actual death certificate, but it’s clearly a better source than the index entry at Ancestry. You can see that someone transposed the columns for year of death and age at death. James died in 1964 at the age of 77, not in 1977.
I have no idea when or how the Ancestry index page was changed. Usually when a user submits an edit, they retain the original information, so you can see that it was changed, and they give a link to the edit and the person who submitted it. This gives no hint that it was ever other than it is now.
James isn’t part of my main line, so I’m not likely to order his death certificate. The index entry may be all I ever have to prove his death date and place. It’s supported by the Social Security Death Index and a photo of his grave marker at Findagrave. None of those is, by itself, sufficient, but together they provide proof enough for me, given that this is a collateral line.