理由是，对一个5岁的孩子来说，他很难和比他早几个月出生的孩子相处。

　　But most parents, one suspects, think that whatever disadvantage a younger child faces in kindergarten eventually goes away.

　　但是大部分儿童家长想当然地以为，不管自己年龄偏小的孩子起初处于怎样不利的地位，这种劣势最终都会在幼儿园被改变过来，

　　But it doesn't. It's just like hockey.

　　但这仅是一厢情愿。这将又是一个曲棍球怪圈。

　　The small initial advantage of the child born in the early part of the year

　　一个学年中早期出生的儿童比晚期出生儿童的这点优势，

　　has over the child over born at the end of the year persists.

　　始终都会存在。

　　It locks children into patterns of achievement and underachievement,

　　从这时始, 这些孩子就被贴上了杰出者、非杰出者，

　　encouragement and discouragement,

　　他们或得到鼓励或受到冷遇，

　　that stretch on for years and years.

　　这种不同的待遇将长时间存在。

　　Recently, two economists, Kelly Bedard and Elizabeth Dhuey,

　　最近，两位经济学家——凯利·贝达德和伊丽莎白·杜伊

　　decided to look at the relationship between scores on what' called TIMSS

　　曾对参与TIMSS的青少年的出生月份和其测试成绩的相关性进行了分析。

　　the math and science tests given every four years to children around the world

　　国际数学和科学评测趋势的简称，每四年对全国青少年进行一次数学和科学能力的测试

　　They found that among fourth graders,

　　她们发现，在四年级的学生中，

　　the oldest children scored somewhere between four and twelve percentile points better than the youngest children.

　　同一年龄出生最早的孩子比出生最晚的孩子，成绩高出4到12分。

　　That, as Dhuey explains, is a "huge effect."

　　杜伊认为这种差別“影响深远”。

　　It means that if you take two intellectually equivalent fourth graders

　　这意味着，两个智商相等的，

　　with birthdays at opposite ends of the cutoff date,

　　但是出生日期不同的四年级小孩，

　　the older student could score in the eightieth percentile,

　　如果出生较早的小孩能够获得80分的测试成绩，

　　while the younger one could score in the sixty-eighth percentile.

　　那么比他出生晚的小孩测试的成绩就可能只是68分。

　　That's a difference between qualifying for a gifted program and not.

　　这种成绩上的差距决定了谁能够羸得掊受更好教育的资格，谁将被淘汰。

　　"It's just like sports," Dhuey said.

　　“这就好像是体育运动”杜伊说，

　　"We do ability grouping early on in childhood,

　　“我们在很小的时候就依据个人能力被划分了类别，

　　we have advanced reading groups and advanced math groups.

　　例如谁拥有阅读的天赋，谁拥有数学特长。

　　So, early on, if we look at young kids in kindergarten and first grade,

　　所以，在一个人很小的时候，当他在幼儿园和一年级的老师观察他的能力时，

　　the teachers are confusing maturity with ability.

　　他的老师常常会被其年龄优势蒙蔽。

　　And they put the older kids in the advanced stream, where they learn better skills;

　　教师们常常会把年龄较大的学生划到优等生里面，这些优等生能学到更多知识；

　　and the next year, because they are in the higher groups, they do even better;

　　第二年，优等生的地位保证了他们的成绩更为优秀，

　　and the next year, the same thing happens, and they do even better again.

　　再过一年，同样的优势可能保证他们进入拔尖学生的行列。

　　The only country we don't see this going on is in Denmark.

　　在我们考察的国家中，唯有丹麦没有这类现象。

　　They have a national policy where they have no ability grouping until the age of ten."

　　他们的政策规定，不能对10岁之前的孩子进行优等生或者普通生的划分。

　　In other words, Denmark waits to make selection decisions

　　换言之，丹麦的教育体制，

　　until maturity differences by age have evened out.

　　必须在消除掉孩子的年龄差别之后，才进行选拔。

　　Dhuey and Bedard subsequently did the same analysis,

　　随后，杜伊和贝达德又进行了统计分析，

　　only this time looking at college.

　　这一次的对象是针对大学生。

　　What do they find?

　　她们的发现如何？

　　At four-year colleges in the United States,

　　在美国四年制的大学中，

　　the highest stream of postsecondary education,

　　这里拥有美国最好的高等教育，

　　students belongs to the relatively youngest group in their class

　　每个年级同一年龄但出生相对较晚的学生人数，

　　are underrepresented by about 11.6 percent.

　　所占的比例不到11.6%。