One very interesting phenomena involves the appearances of duplicates as information is added to the entries through research and attached as sources. For example, I began searching for the wife of a relative that was shown a unmarried and who was born and died in England. My relative has a very common name: John Briant (also spelled Bryant). I checked to see if there were any duplicates for him in the Family Tree and none were found. I decided to see if he ever married and began doing research. Almost immediately, I found a marriage record that identified his wife's name as "Susan."
I did some additional research and found more records. It seems that adding a wife's name (or spouse's name) assists the search engine in finding additional information. I then found a marriage record that identified the wife's father, thereby providing her with a surname. I continued to do research and now found even more records. What was interesting is that I also began to find duplicate records in the system. Every time I added more researched information about the family, I found additional duplicates. At any point from when I first identified the wife's name. I could have printed ordinance cards. But I decided to add additional information on the hope that there were some children in the newly identified family.
But as I continued to add information and sources, I got even more duplicates. There seems to be a direct correlation between adding source information and detecting more duplicates in the Family Tree. So, it would also appear, that researchers who stop short of discovering additional source information about the people they identify run the real risk of duplicating ordinances. When I first identified the wife, I found no duplicates. It was only as I added specific information from several sources that the duplicates appeared. I am guessing that this is why I found several duplicate entries for this same couple with almost no information, just the bare names and dates with incomplete places. Apparently, the program does not find duplicates without a certain level of information about the individuals.
I realized that I had been seeing this phenomena before without realizing exactly what was happening. I suggest that the number of duplicate entries in the program will continue to increase if the contributors fail to add sources to the information they supply and then add the information from the sources to the entries and keep searching multiple times for duplicates entries.