There are two sources on-line for British Empire casualties; Ancestry and The Register which is the one I have been compiling for about ten years now.
The Ancestry data comes from Naval & Military a well known publisher of military history books, maps and other source material.
In helping a family history researcher on AngloBoerwar.com I was made aware that the casualty data on Ancestry compiled by Naval & Military has been edited to remove facts such as the severity of a wound (slight, severe, dangerous), cause of death and most importantly dates of death. This last piece of information really important and knowing the severity of a wound adds colour to the story of a man's military service.
I have found a number of examples where the wound data is abbreviated to just "Wounded":
Pte 29832 WH Grantham IY - "Dangsly wounded Accidentally"
Pte 32616 J Renton IY - "Sev wounded Self Inflicted"
Pte 26744 JH Wilson IY -"Slightly wounded"
Dates of death published in the casualty roll are missing from Ancestry, here are two examples:
Pte 482 AL Tilley SAC - "Wounded 9-11-1901 Died 13-11-1901" - the wounding is shown but the date of death is omitted, and the same for Pte 31776 LR Stewart Scottish Horse
Some men died of unusual causes which are not noted in Ancestry, but simply recorded as "Died" or "Killed":
Pte B Smith, Nesbitt's Horse - bee stings
Trpr TC Fenton, BSAP - killed by a lioness
Trpr S Smart Steinaecker's Horse - killed by a lion
Pte W Cunningham 2nd Dragoons - gored by a bull
The internet has been hugely positive in making research material more easily available. But, where the data has been pulled from original material it is clear some companies are more concerned with profit and show little respect for the historical record or the people they expect to pay to view the data.
There are also errors in the Ancestry casualty records, the non-existent 12th Hussars make an appearance: Pte 3098 W Muirhead was in the 13th Hussars. Such errors are in every single source I have consulted to build The Register which is the only casualty roll that is corrected and enhanced. When errors are found in The Register, they are fixed immediately - no other online resource does this.
And when looking at casualties The Register offers unique gazetteer data to help you locate the place a casualty occurred.