www.wrightslaw.com is a great resource

Usually a student is tested for both intelligence quotient and current achievement levels and this is expressed in standard scores. For instance, if your child receives an IQ score of 100, then achievement must fall at 85 or below in reading, written language or math to qualify for Special Ed. This is considered a severe discrepancy between ability and achievement. If they score 110 as an IQ score, then achievement has to be 95 or below. Subtract 23 points if your child is older than twelve.

In addition, you child must have a documented learning disability or emotional handicap.

During the re-authorization of IDEA in 2004, the discrepancy was no longer required. However, each state will interpret the new law its own way and it will be interested to see how it plays out, which will not be any time soon.

You mentioned, physical, mental or percentile as standards. All three can be used to make that determination. There are criteria but to say they are typical would be misleading. So, I will try to assist you.

If the child is two years or more behind peers academically, a learning disability could be the issue.

If the child is two or more years developmentally behind than peers, there could be a developmental delay (walking, talking, feeding self, toileting-although this is an area of great disagreement, playing with others, playing with different toys, playing with age appropriate toys).

Percentile rankings are done with state wide tests and academic assessments.

As a parent, please, ask as many professionals, parents, and others to educate yourself. Do that which is best for your child and your family. Good luck.

But–as I said, in practice, its not done that way in many school systems. There is overwhelming documentation that shows minority status (e.g. children for whom English is a second language), race, and socio-economic background correlate strongly with labeling children as “special needs” and (supposedly) disabled. Also, many children with behavioral problems are often more or less arbitrarly labeled as having a disability–and school officials are often not required to follow proper procedures for diagnosis and assessment. And it is often easier–and therefore tempting–to simple label a child who is a problem in class and move him/her out to a special ed classroom.

In addition, although the “Individual Education Plan” system is well-intentioned, it has some serious flaws. The most serious is that students on an IEP are not, per se, entitled to the same educational opportunities as other children, as are children with disabilities under a Section 504 plan. There are good reasons for this provision–some children are far better off with a modified curriculum and may not be able to handle the regular academic matieral. But again, there is an overwhelming body of evidence that this provision is being used as a loophole for schools to avoid accountability for outcomes–to the detriment of many special needs children who could and should receive the full rane of academic opportunities and aren’t getting them–and aren’t getting high school diplomas, either.

Don’t get me wrong–there are good criteria–and some schools and educators are using them properly and doing an outstanding job. But the majority are not–this is a system that is badly in need of serious reform.