Grade skipping

Grade skipping is a form of academic acceleration, often used for academically talented students, that enable the student to skip entirely the curriculum of one or more years of school. This is done when a student is sufficiently advanced in all school subjects, so that they can move forward in all subjects or graduate, rather than in only one or two areas.
Timing and other factors.
Grade acceleration is easiest to implement through skipping pre-kindergarten into kindergarten or skipping kindergarten into first grade directly. By starting the child ahead, many of the problems associated with grade skipping, such as leaving friends behind or knowledge gaps, are avoided.
Other key factors to a successful grade skip include the desire of the student, the receptivity of the receiving teacher, and whether a sibling is in the old or new grade. All these factors have been studied and organized into a survey called "The Iowa Acceleration Scale" (IAS)"," which when completed yields a recommendation on whether or not to accelerate. The IAS also cited four critical situations where grade skipping is not recommended. These conditions are:
Cost-effectiveness.
Grade skipping is one of the most cost-effective ways of addressing the needs of a profoundly gifted student, as it requires no extra resources and very little more than assigning the child to a different classroom, without the expense of special materials, tutoring or separate programs. The cost of educating the gifted child in a regular classroom with typical same-age peers is the same as the cost of educating that child in a regular classroom with typical somewhat older students, so using grade skipping is essentially cost-free. Students may benefit financially from grade skipping, as recent research shows that children who skipped a grade earn higher incomes in adulthood than similar non-skipping students.
Potential problems.
Many academic administrators and the general public carry misconceptions about grade skipping, believing that children are often harmed by being placed in an environment for which they are academically ready but emotionally or socially not.
Knowledge gaps.
The time that the student skips may create a knowledge gap if the child has not self-studied the material already taught to the students in the grade being entered. While the student is bridging this gap they will likely find the new material challenging. It may be demoralizing to leave a situation in which they are top performers into a situation where they are struggling with the material. Knowledge gaps are smaller in earlier school years. Students almost always successfully catch up to match their peers.
Friendships.
Students entering a new grade after being in school are taken out of their existing peer group and put into a new group, essentially leaving friends behind and being forced to make new friends. Although this is perceived as a problem, and certainly being displaced is a trial for the student, it is often the case with gifted children that they are more easily able to relate to older children than children their age. Regardless, there will likely be a period of stress while the student integrates into the new class.
Other social concerns.
Students in the new class may view the skipping student as different. This may result in additional social problems such as teasing or perceived preferential treatment. There is also the perception that the learner could be ostracized for being accelerated. For boys, skipping students who are large in stature and athletically oriented are at an advantage in that they have a smaller likelihood of being teased or picked on. In the adolescent years when most students are "discovering" sexual feelings, the young skipping student may have problems. The skipping adolescent's hormone development might not yet have created sexual interest in their peers, while most of the classmates can be preoccupied with socializing. 
Holding back.
By the beginning of the 21st century, many American parents were using a strategy of holding children back, starting school later and/or not advancing a grade. The reason is that with the extra year or so of physical and social maturity, the child will more likely become a leader and have more peer approval. Skipping a student is just the opposite. A skipped child may enter a class that includes a few children who have been held back and are two years older and more mature.
Advanced classes.
Advancing in a class is not necessarily grade skipping. Rather, it is more for people who show a much higher level of intelligence, while the other students are left in the grade-level class. For example, an eighth-grade student who is doing very well in his advanced algebra classes, but finds them too easy for him, may be given an option to take a test, and if he passes the test, he may be moved up to geometry or whatever the next level up mathematically may be while still in eighth grade. His schedule does change, but usually only one class is substituted.
Resistance.
Grade skipping allows students to learn at a level appropriate for their cognitive abilities. For the majority of gifted students, grade skipping is beneficial both academically "and" socially.
American schools may oppose grade skipping, or limit it to one or at the most two grades, regardless of the student's academic and social situation. There is no research that supports these limits, and the decision to limit grade skipping is mostly based on the intuition of school personnel or the administration's lack of knowledge regarding possible academic and social benefits. Refusing to promote the student to an appropriate level can result in social isolation and educational underachievement.