FamilySearch.org Family Tree is like a very old house that is in the process of being remodeled. The original contents of the Family Tree are a huge accumulation of years of submissions for over a hundred years. Added to that original pile are all the submissions made to the new.FamilySearch.org program and now the Family Tree. Unfortunately, this "remodeling" effort is going on while we live in the house, i.e. keep using the Family Tree. We need to keep reminding ourselves that we bought this house (Family Tree) without a home warranty and without even a prior-to-occupancy home inspection.
The first order of business when beginning this remodeling effort is to assess the condition of the premises. Likewise, with the Family Tree, anyone approaching the information already present needs to be examining that information carefully. Just as you cannot assume that there are not a few hidden defects in an old house, you cannot blissfully assume that everything in your part of the Family Tree is either complete or accurate. Let me give several examples from my portion of the Family Tree.
I will start with four family lines; the Tanners, the Parkinsons, the Oversons, and the Jarvis families. These are the surnames of my four great-grandparents. The process begins with my own personal record and for this illustration, I will avow that I have carefully examined the entries for my parents and grandparents. My task is to look at each person in each of the lines and see where that particular line "ends" because of lack of information or entries that have serious data errors. My personal rule here is that any entry without supporting source citations is suspect. Of course, as I go back in time on my family lines, the number of surnames (i.e. family lines) doubles with each generation. But for this example, I will stick to the four surname lines above. I have to admit that I have already gone through this process so I have a pretty good idea where the lines end and the fantasy world begins.
First one up is the Tanner line. Moving back generation by generation and after carefully examining all of the sources, I find that the line ends with Francis Tanner, b. 1708, d. 1777. Why is this the case? There is not one source listed connecting Francis Tanner to his father other than a reference to a book that has no supporting sources listed. Traditionally, the Tanner line goes on for one more generation (or several more with what is in the Family Tree) but no one has ever found any record substantiating Francis Tanner's parents. If I need any justification for this opinion, all I have to do is look at his "father" William Tanner. Presently, the Family Tree shows him born in Chipstead, Surrey, England in 1657 and shows the line going back in England. However, there are no records showing any connection between William Tanner in Rhode Island and anyone in England. In addition, the dates for William Tanner and his three wives don't make any sense at all. End of Line.
The next line to examine is the Parkinsons. I have done extensive research on the Parkinson line in conjunction with one of my daughters and her husband who is also a Parkinson. This line effectively ends with Charles Parkinson, b. 1766, d. 1846. We have no documentation connecting him to his father in the Family Tree. In fact, the Family Tree presently shows that Charles' birth date is two years before the date recorded for his parents' marriage date and there are no records either supporting his birth date or the identity of his parents. End of Line.
The Overson line goes back to Denmark, so the surname is really Ovesen (but there is some record of the name being Oveson, with an "o" in Denmark). The line effectively ends at the immigrant, Jens Andreas Ovesen. The dates and places beyond that are so confused as to be indecipherable. The main problems is that the children listed are all ove the place in different parishes. End of Line.
The last line in this example is the Jarvis line. This is easy. Charles Godfrey DeFriez Jarvis, b. 1855, d. 1919, changed his name from DeFriez to Jarvis. So he is really a DeFriez. The DeFriez line goes back to Marcus Mordecai Jacob DeVries in the Netherlands, but there no real documentation at this point to connect the family in England to the one the Netherlands. End of Line.
If you follow this analysis on every line, you will soon see that the old data in the Family Tree is in a dire need of remodeling. So it is time to get out the "detach" tool and to mix metaphores, prune the tree.