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What Is Full Scale Intelligence Quotient (FSIQ)?

Full Scale Intelligence Quotient (FSIQ)

Full-Scale Intelligence Quotient (FSIQ) is a term coined for an individual’s complete cognitive capacity. With regard to children, the Wechsler Intelligence Scale for Children (WISC) is the most commonly used test in helping measure a child’s mental capacity. Children with autism spectrum disorder (ASD or autism), more often than not, require special education to help them improve and develop skills despite their developmental disability.

David Wechsler originally developed WISC in 1949. In 2003, the fourth and latest edition of WISC was published and is presently being used by practitioners to determine the intellectual strengths and weaknesses of children ages 6–16. The WISC-IV consists of four different indexes, each with its own subtests, named as follows:

Verbal Comprehension Index (VCI)

  •  Similarities – Here your child is asked what likeness two different words have.
  • Vocabulary – Your child is usually given 35 words to define.
  • Comprehension – Here your child is asked 16 questions that pertain to social situations.
  •  Information – This is usually a 29-question subtest about general knowledge.
  • Word Reasoning – Here your child is given a word related to a specific object or a word that your child needs to be able to say.

Perceptual Reasoning Index (PRI)

  • Block design – This is a timed test with your child copying a presented model with the use of blocks.
  • Picture concepts – Your child is asked to identify pictures that go together in a series of pictures laid out in rows.
  • Matrix reasoning – Here your child is presented with a series of pictures and will be asked to fill in the missing detail.
  • Picture completion – Your child points or names a missing part of a picture that is presented to him.

Working Memory Index (WMI)

  • Digit span – Here your child is given a series of numbers and is asked to repeat it either in sequence or in reverse order.
  • Letter-number sequencing – Here your child is given a set of numbers and letters. The examiner will then ask for a prearranged order.
  • Arithmetic – This is a timed oral questioning of arithmetic questions.
  • Processing Speed Index (PSI)
  • Coding – This is a timed subtest wherein children are asked to write a digit-symbol code.
  • Symbol search – Here, a row of symbols and a “target” symbol are presented to your child. Your child is then asked if the target symbol is present in each row.
  • Cancellation – Here your child is presented with random pictures where he is to mark target symbols given by the examiner under time pressure.

The WISC-IV provides supplemental subtests that are used as alternatives or replacements to other subtests that yielded inaccurate or wrong results due to rare circumstances. According to the WISC-IV, examinees are only allowed no more than two substitutions in an FSIQ test or not more than one substitution per index. The subtests are the following:

  • Information
  • Word reasoning
  • Picture completion
  • Arithmetic
  • Cancellation

FSIQ test is conducted between 60 and 80 minutes, in total. Some children may take longer if the supplemental subtests are given. FSIQ results can range from 40 being the lowest and 160 being the highest. The average mean score is typically 100.


Concord SEPAC, concordspedpac.org: Wechsler Intelligence Scale for Children (WISC), Retrieved March 23, 2011, from http://www.concordspedpac.org/WISC_IV.html

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Parent Waitlist Program


November 02, 2023 | 12pm-1pm PDT

Journey to Independence

Community-based program designed to support families on waitlist

Being an RBT for me was extremely fun because where were you going to find a place where you can be completely silly without having to worry what people thought about you? This was the only job that made me feel like I could make a dramatic difference while being myself.

I also liked to be surrounded by people that had the same goals of wanting to help kids and the teamwork made the job much easier and more enjoyable.

Change and progress was the ultimate goal for our kiddos. The early intervention program was seriously only a miracle because I saw changes in the kiddos that from day one, you wouldn’t even recognize who they were.

Changes from being able to utter 3-4 words where they can only make a syllable from when they started, the behavior decreases in which kiddo that used to engage in 30-40 0 self-harm to only half, learning how to wait during games, table work where they use to swipe and drop to the floor if they had to.

My favorite was when the parents would tell us what amazing progress they were making at home. I used to tear up and felt for these parents so much because it was already difficult for them and now, they can trust and rely on ABA and the therapists knowing their goal was ours.

By Emma Rogers, BA, RBT

Mother Child
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