The Kinderdarten Debate

In the book Outliers, Malcolm Gladwell says that being delayed in your early life and being held back from kindergarten and sports is a good thing. He says it leads to an "accumulative advantage that will allow you to think and physically perform better than other kids in your grade. However, Sam Wang and Sandra Aamodt have wrote an article that preaches why holding your kid back is a bad idea. They say that "Red shirting...can lead to less motivation than their peers."However they explain how they are the ones that are solely right, lets look at the arguments. These two pieces of work literally disagree on everything except that being held back helps sports. All that these article say is what they believe. Both articles have statistics to back them. For example, Sam and Sandra's article states that "In a class of 25, the average difference is equivalent to going from 13th place to 11th. This advantage fades by the end of elementary school, though, and disadvantages start to accumulate." However, Malcolm counters by showing that Most hockey players were born in January, February, and March, and January 1 is the cutoff. All of these kids proved to some how "...be bigger, faster, and more responsible than their team-mates."
So who to believe? The only thing I can go on is my personal experience. I know, or have known, several people who started school early. They are smart, but often less mature than their peers. They also have a harder time making friends. I also know that the principals for children who are older seem to be the same. They often are very smart, sometimes too advanced in their maturity level, and have a difficulty making friends. But there are always outliers. Some kids who were held back easily make friends, seem to be slightly less intelligent, and have average maturity. I have come to believe that neither party is wrong, but that success and failure depends on the child.